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PCI/VGA: Fix typos

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Fix typos, rewrap to fill 78 columns, convert to conventional multi-line
style.

[bhelgaas: squash and add more fixes]
Link: https://lore.kernel.org/r/20230808223412.1743176-7-sui.jingfeng@linux.dev
Link: https://lore.kernel.org/r/20230808223412.1743176-9-sui.jingfeng@linux.dev
Link: https://lore.kernel.org/r/20230808223412.1743176-10-sui.jingfeng@linux.dev
Link: https://lore.kernel.org/r/20230808223412.1743176-11-sui.jingfeng@linux.dev
Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Sui Jingfeng
2023-08-09 06:34:07 +08:00
committed by Bjorn Helgaas
parent 0215845348
commit cc64ca4b62
2 changed files with 161 additions and 151 deletions
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306
drivers/pci/vgaarb.c
View File

@@ -1,6 +1,6 @@
// SPDX-License-Identifier: MIT // SPDX-License-Identifier: MIT
/* /*
* vgaarb.c: Implements the VGA arbitration. For details refer to * vgaarb.c: Implements VGA arbitration. For details refer to
* Documentation/gpu/vgaarbiter.rst * Documentation/gpu/vgaarbiter.rst
* *
* (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org> * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
@@ -30,22 +30,21 @@
#include <linux/vt.h> #include <linux/vt.h>
#include <linux/console.h> #include <linux/console.h>
#include <linux/acpi.h> #include <linux/acpi.h>
#include <linux/uaccess.h> #include <linux/uaccess.h>
#include <linux/vgaarb.h> #include <linux/vgaarb.h>
static void vga_arbiter_notify_clients(void); static void vga_arbiter_notify_clients(void);
/* /*
* We keep a list of all vga devices in the system to speed * We keep a list of all VGA devices in the system to speed
* up the various operations of the arbiter * up the various operations of the arbiter
*/ */
struct vga_device { struct vga_device {
struct list_head list; struct list_head list;
struct pci_dev *pdev; struct pci_dev *pdev;
unsigned int decodes; /* what does it decodes */ unsigned int decodes; /* what it decodes */
unsigned int owns; /* what does it owns */ unsigned int owns; /* what it owns */
unsigned int locks; /* what does it locks */ unsigned int locks; /* what it locks */
unsigned int io_lock_cnt; /* legacy IO lock count */ unsigned int io_lock_cnt; /* legacy IO lock count */
unsigned int mem_lock_cnt; /* legacy MEM lock count */ unsigned int mem_lock_cnt; /* legacy MEM lock count */
unsigned int io_norm_cnt; /* normal IO count */ unsigned int io_norm_cnt; /* normal IO count */
@@ -61,7 +60,6 @@ static bool vga_arbiter_used;
static DEFINE_SPINLOCK(vga_lock); static DEFINE_SPINLOCK(vga_lock);
static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
static const char *vga_iostate_to_str(unsigned int iostate) static const char *vga_iostate_to_str(unsigned int iostate)
{ {
/* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */
@@ -79,14 +77,16 @@ static const char *vga_iostate_to_str(unsigned int iostate)
static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state) static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state)
{ {
/* we could in theory hand out locks on IO and mem /*
* separately to userspace but it can cause deadlocks */ * In theory, we could hand out locks on IO and MEM separately to
* userspace, but this can cause deadlocks.
*/
if (strncmp(buf, "none", 4) == 0) { if (strncmp(buf, "none", 4) == 0) {
*io_state = VGA_RSRC_NONE; *io_state = VGA_RSRC_NONE;
return 1; return 1;
} }
/* XXX We're not chekcing the str_size! */ /* XXX We're not checking the str_size! */
if (strncmp(buf, "io+mem", 6) == 0) if (strncmp(buf, "io+mem", 6) == 0)
goto both; goto both;
else if (strncmp(buf, "io", 2) == 0) else if (strncmp(buf, "io", 2) == 0)
@@ -99,7 +99,7 @@ both:
return 1; return 1;
} }
/* this is only used a cookie - it should not be dereferenced */ /* This is only used as a cookie, it should not be dereferenced */
static struct pci_dev *vga_default; static struct pci_dev *vga_default;
/* Find somebody in our list */ /* Find somebody in our list */
@@ -116,20 +116,18 @@ static struct vga_device *vgadev_find(struct pci_dev *pdev)
/** /**
* vga_default_device - return the default VGA device, for vgacon * vga_default_device - return the default VGA device, for vgacon
* *
* This can be defined by the platform. The default implementation * This can be defined by the platform. The default implementation is
* is rather dumb and will probably only work properly on single * rather dumb and will probably only work properly on single VGA card
* vga card setups and/or x86 platforms. * setups and/or x86 platforms.
* *
* If your VGA default device is not PCI, you'll have to return * If your VGA default device is not PCI, you'll have to return NULL here.
* NULL here. In this case, I assume it will not conflict with * In this case, I assume it will not conflict with any PCI card. If this
* any PCI card. If this is not true, I'll have to define two archs * is not true, I'll have to define two arch hooks for enabling/disabling
* hooks for enabling/disabling the VGA default device if that is * the VGA default device if that is possible. This may be a problem with
* possible. This may be a problem with real _ISA_ VGA cards, in * real _ISA_ VGA cards, in addition to a PCI one. I don't know at this
* addition to a PCI one. I don't know at this point how to deal * point how to deal with that card. Can their IOs be disabled at all? If
* with that card. Can theirs IOs be disabled at all ? If not, then * not, then I suppose it's a matter of having the proper arch hook telling
* I suppose it's a matter of having the proper arch hook telling * us about it, so we basically never allow anybody to succeed a vga_get().
* us about it, so we basically never allow anybody to succeed a
* vga_get()...
*/ */
struct pci_dev *vga_default_device(void) struct pci_dev *vga_default_device(void)
{ {
@@ -147,14 +145,13 @@ void vga_set_default_device(struct pci_dev *pdev)
} }
/** /**
* vga_remove_vgacon - deactivete vga console * vga_remove_vgacon - deactivate VGA console
* *
* Unbind and unregister vgacon in case pdev is the default vga * Unbind and unregister vgacon in case pdev is the default VGA device.
* device. Can be called by gpu drivers on initialization to make * Can be called by GPU drivers on initialization to make sure VGA register
* sure vga register access done by vgacon will not disturb the * access done by vgacon will not disturb the device.
* device.
* *
* @pdev: pci device. * @pdev: PCI device.
*/ */
#if !defined(CONFIG_VGA_CONSOLE) #if !defined(CONFIG_VGA_CONSOLE)
int vga_remove_vgacon(struct pci_dev *pdev) int vga_remove_vgacon(struct pci_dev *pdev)
@@ -193,14 +190,17 @@ int vga_remove_vgacon(struct pci_dev *pdev)
#endif #endif
EXPORT_SYMBOL(vga_remove_vgacon); EXPORT_SYMBOL(vga_remove_vgacon);
/* If we don't ever use VGA arb we should avoid /*
turning off anything anywhere due to old X servers getting * If we don't ever use VGA arbitration, we should avoid turning off
confused about the boot device not being VGA */ * anything anywhere due to old X servers getting confused about the boot
* device not being VGA.
*/
static void vga_check_first_use(void) static void vga_check_first_use(void)
{ {
/* we should inform all GPUs in the system that /*
* VGA arb has occurred and to try and disable resources * Inform all GPUs in the system that VGA arbitration has occurred
* if they can */ * so they can disable resources if possible.
*/
if (!vga_arbiter_used) { if (!vga_arbiter_used) {
vga_arbiter_used = true; vga_arbiter_used = true;
vga_arbiter_notify_clients(); vga_arbiter_notify_clients();
@@ -216,7 +216,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
unsigned int pci_bits; unsigned int pci_bits;
u32 flags = 0; u32 flags = 0;
/* Account for "normal" resources to lock. If we decode the legacy, /*
* Account for "normal" resources to lock. If we decode the legacy,
* counterpart, we need to request it as well * counterpart, we need to request it as well
*/ */
if ((rsrc & VGA_RSRC_NORMAL_IO) && if ((rsrc & VGA_RSRC_NORMAL_IO) &&
@@ -236,14 +237,15 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
if (wants == 0) if (wants == 0)
goto lock_them; goto lock_them;
/* We don't need to request a legacy resource, we just enable /*
* appropriate decoding and go * We don't need to request a legacy resource, we just enable
* appropriate decoding and go.
*/ */
legacy_wants = wants & VGA_RSRC_LEGACY_MASK; legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
if (legacy_wants == 0) if (legacy_wants == 0)
goto enable_them; goto enable_them;
/* Ok, we don't, let's find out how we need to kick off */ /* Ok, we don't, let's find out who we need to kick off */
list_for_each_entry(conflict, &vga_list, list) { list_for_each_entry(conflict, &vga_list, list) {
unsigned int lwants = legacy_wants; unsigned int lwants = legacy_wants;
unsigned int change_bridge = 0; unsigned int change_bridge = 0;
@@ -252,39 +254,44 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
if (vgadev == conflict) if (vgadev == conflict)
continue; continue;
/* We have a possible conflict. before we go further, we must /*
* We have a possible conflict. Before we go further, we must
* check if we sit on the same bus as the conflicting device. * check if we sit on the same bus as the conflicting device.
* if we don't, then we must tie both IO and MEM resources * If we don't, then we must tie both IO and MEM resources
* together since there is only a single bit controlling * together since there is only a single bit controlling
* VGA forwarding on P2P bridges * VGA forwarding on P2P bridges.
*/ */
if (vgadev->pdev->bus != conflict->pdev->bus) { if (vgadev->pdev->bus != conflict->pdev->bus) {
change_bridge = 1; change_bridge = 1;
lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
} }
/* Check if the guy has a lock on the resource. If he does, /*
* return the conflicting entry * Check if the guy has a lock on the resource. If he does,
* return the conflicting entry.
*/ */
if (conflict->locks & lwants) if (conflict->locks & lwants)
return conflict; return conflict;
/* Ok, now check if it owns the resource we want. We can /*
* lock resources that are not decoded, therefore a device * Ok, now check if it owns the resource we want. We can
* lock resources that are not decoded; therefore a device
* can own resources it doesn't decode. * can own resources it doesn't decode.
*/ */
match = lwants & conflict->owns; match = lwants & conflict->owns;
if (!match) if (!match)
continue; continue;
/* looks like he doesn't have a lock, we can steal /*
* them from him * Looks like he doesn't have a lock, we can steal them
* from him.
*/ */
flags = 0; flags = 0;
pci_bits = 0; pci_bits = 0;
/* If we can't control legacy resources via the bridge, we /*
* If we can't control legacy resources via the bridge, we
* also need to disable normal decoding. * also need to disable normal decoding.
*/ */
if (!conflict->bridge_has_one_vga) { if (!conflict->bridge_has_one_vga) {
@@ -311,7 +318,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
} }
enable_them: enable_them:
/* ok dude, we got it, everybody conflicting has been disabled, let's /*
* Ok, we got it, everybody conflicting has been disabled, let's
* enable us. Mark any bits in "owns" regardless of whether we * enable us. Mark any bits in "owns" regardless of whether we
* decoded them. We can lock resources we don't decode, therefore * decoded them. We can lock resources we don't decode, therefore
* we must track them via "owns". * we must track them via "owns".
@@ -353,8 +361,9 @@ static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
vgaarb_dbg(dev, "%s\n", __func__); vgaarb_dbg(dev, "%s\n", __func__);
/* Update our counters, and account for equivalent legacy resources /*
* if we decode them * Update our counters and account for equivalent legacy resources
* if we decode them.
*/ */
if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) {
vgadev->io_norm_cnt--; vgadev->io_norm_cnt--;
@@ -371,32 +380,34 @@ static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0)
vgadev->mem_lock_cnt--; vgadev->mem_lock_cnt--;
/* Just clear lock bits, we do lazy operations so we don't really /*
* have to bother about anything else at this point * Just clear lock bits, we do lazy operations so we don't really
* have to bother about anything else at this point.
*/ */
if (vgadev->io_lock_cnt == 0) if (vgadev->io_lock_cnt == 0)
vgadev->locks &= ~VGA_RSRC_LEGACY_IO; vgadev->locks &= ~VGA_RSRC_LEGACY_IO;
if (vgadev->mem_lock_cnt == 0) if (vgadev->mem_lock_cnt == 0)
vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
/* Kick the wait queue in case somebody was waiting if we actually /*
* released something * Kick the wait queue in case somebody was waiting if we actually
* released something.
*/ */
if (old_locks != vgadev->locks) if (old_locks != vgadev->locks)
wake_up_all(&vga_wait_queue); wake_up_all(&vga_wait_queue);
} }
/** /**
* vga_get - acquire & locks VGA resources * vga_get - acquire & lock VGA resources
* @pdev: pci device of the VGA card or NULL for the system default * @pdev: PCI device of the VGA card or NULL for the system default
* @rsrc: bit mask of resources to acquire and lock * @rsrc: bit mask of resources to acquire and lock
* @interruptible: blocking should be interruptible by signals ? * @interruptible: blocking should be interruptible by signals ?
* *
* This function acquires VGA resources for the given card and mark those * Acquire VGA resources for the given card and mark those resources
* resources locked. If the resource requested are "normal" (and not legacy) * locked. If the resources requested are "normal" (and not legacy)
* resources, the arbiter will first check whether the card is doing legacy * resources, the arbiter will first check whether the card is doing legacy
* decoding for that type of resource. If yes, the lock is "converted" into a * decoding for that type of resource. If yes, the lock is "converted" into
* legacy resource lock. * a legacy resource lock.
* *
* The arbiter will first look for all VGA cards that might conflict and disable * The arbiter will first look for all VGA cards that might conflict and disable
* their IOs and/or Memory access, including VGA forwarding on P2P bridges if * their IOs and/or Memory access, including VGA forwarding on P2P bridges if
@@ -428,7 +439,7 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
int rc = 0; int rc = 0;
vga_check_first_use(); vga_check_first_use();
/* The one who calls us should check for this, but lets be sure... */ /* The caller should check for this, but let's be sure */
if (pdev == NULL) if (pdev == NULL)
pdev = vga_default_device(); pdev = vga_default_device();
if (pdev == NULL) if (pdev == NULL)
@@ -447,12 +458,12 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
if (conflict == NULL) if (conflict == NULL)
break; break;
/*
/* We have a conflict, we wait until somebody kicks the * We have a conflict; we wait until somebody kicks the
* work queue. Currently we have one work queue that we * work queue. Currently we have one work queue that we
* kick each time some resources are released, but it would * kick each time some resources are released, but it would
* be fairly easy to have a per device one so that we only * be fairly easy to have a per-device one so that we only
* need to attach to the conflicting device * need to attach to the conflicting device.
*/ */
init_waitqueue_entry(&wait, current); init_waitqueue_entry(&wait, current);
add_wait_queue(&vga_wait_queue, &wait); add_wait_queue(&vga_wait_queue, &wait);
@@ -474,12 +485,12 @@ EXPORT_SYMBOL(vga_get);
/** /**
* vga_tryget - try to acquire & lock legacy VGA resources * vga_tryget - try to acquire & lock legacy VGA resources
* @pdev: pci devivce of VGA card or NULL for system default * @pdev: PCI device of VGA card or NULL for system default
* @rsrc: bit mask of resources to acquire and lock * @rsrc: bit mask of resources to acquire and lock
* *
* This function performs the same operation as vga_get(), but will return an * Perform the same operation as vga_get(), but return an error (-EBUSY)
* error (-EBUSY) instead of blocking if the resources are already locked by * instead of blocking if the resources are already locked by another card.
* another card. It can be called in any context * Can be called in any context.
* *
* On success, release the VGA resource again with vga_put(). * On success, release the VGA resource again with vga_put().
* *
@@ -495,7 +506,7 @@ static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc)
vga_check_first_use(); vga_check_first_use();
/* The one who calls us should check for this, but lets be sure... */ /* The caller should check for this, but let's be sure */
if (pdev == NULL) if (pdev == NULL)
pdev = vga_default_device(); pdev = vga_default_device();
if (pdev == NULL) if (pdev == NULL)
@@ -515,20 +526,20 @@ bail:
/** /**
* vga_put - release lock on legacy VGA resources * vga_put - release lock on legacy VGA resources
* @pdev: pci device of VGA card or NULL for system default * @pdev: PCI device of VGA card or NULL for system default
* @rsrc: but mask of resource to release * @rsrc: bit mask of resource to release
* *
* This fuction releases resources previously locked by vga_get() or * Release resources previously locked by vga_get() or vga_tryget(). The
* vga_tryget(). The resources aren't disabled right away, so that a subsequence * resources aren't disabled right away, so that a subsequent vga_get() on
* vga_get() on the same card will succeed immediately. Resources have a * the same card will succeed immediately. Resources have a counter, so
* counter, so locks are only released if the counter reaches 0. * locks are only released if the counter reaches 0.
*/ */
void vga_put(struct pci_dev *pdev, unsigned int rsrc) void vga_put(struct pci_dev *pdev, unsigned int rsrc)
{ {
struct vga_device *vgadev; struct vga_device *vgadev;
unsigned long flags; unsigned long flags;
/* The one who calls us should check for this, but lets be sure... */ /* The caller should check for this, but let's be sure */
if (pdev == NULL) if (pdev == NULL)
pdev = vga_default_device(); pdev = vga_default_device();
if (pdev == NULL) if (pdev == NULL)
@@ -665,7 +676,7 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
} }
/* /*
* vgadev has neither IO nor MEM enabled. If we haven't found any * Vgadev has neither IO nor MEM enabled. If we haven't found any
* other VGA devices, it is the best candidate so far. * other VGA devices, it is the best candidate so far.
*/ */
if (!boot_vga) if (!boot_vga)
@@ -696,20 +707,20 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
return; return;
} }
/* okay iterate the new devices bridge hierarachy */ /* Iterate the new device's bridge hierarchy */
new_bus = vgadev->pdev->bus; new_bus = vgadev->pdev->bus;
while (new_bus) { while (new_bus) {
new_bridge = new_bus->self; new_bridge = new_bus->self;
/* go through list of devices already registered */ /* Go through list of devices already registered */
list_for_each_entry(same_bridge_vgadev, &vga_list, list) { list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
bus = same_bridge_vgadev->pdev->bus; bus = same_bridge_vgadev->pdev->bus;
bridge = bus->self; bridge = bus->self;
/* see if the share a bridge with this device */ /* See if it shares a bridge with this device */
if (new_bridge == bridge) { if (new_bridge == bridge) {
/* /*
* If their direct parent bridge is the same * If its direct parent bridge is the same
* as any bridge of this device then it can't * as any bridge of this device then it can't
* be used for that device. * be used for that device.
*/ */
@@ -717,10 +728,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
} }
/* /*
* Now iterate the previous devices bridge hierarchy. * Now iterate the previous device's bridge hierarchy.
* If the new devices parent bridge is in the other * If the new device's parent bridge is in the other
* devices hierarchy then we can't use it to control * device's hierarchy, we can't use it to control this
* this device * device.
*/ */
while (bus) { while (bus) {
bridge = bus->self; bridge = bus->self;
@@ -741,10 +752,9 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
} }
/* /*
* Currently, we assume that the "initial" setup of the system is * Currently, we assume that the "initial" setup of the system is not sane,
* not sane, that is we come up with conflicting devices and let * that is, we come up with conflicting devices and let the arbiter's
* the arbiter's client decides if devices decodes or not legacy * client decide if devices decodes legacy things or not.
* things.
*/ */
static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
{ {
@@ -781,10 +791,12 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
/* by default mark it as decoding */ /* By default, mark it as decoding */
vga_decode_count++; vga_decode_count++;
/* Mark that we "own" resources based on our enables, we will
* clear that below if the bridge isn't forwarding /*
* Mark that we "own" resources based on our enables, we will
* clear that below if the bridge isn't forwarding.
*/ */
pci_read_config_word(pdev, PCI_COMMAND, &cmd); pci_read_config_word(pdev, PCI_COMMAND, &cmd);
if (cmd & PCI_COMMAND_IO) if (cmd & PCI_COMMAND_IO)
@@ -864,7 +876,7 @@ bail:
return ret; return ret;
} }
/* This is called with the lock */ /* Called with the lock */
static void vga_update_device_decodes(struct vga_device *vgadev, static void vga_update_device_decodes(struct vga_device *vgadev,
unsigned int new_decodes) unsigned int new_decodes)
{ {
@@ -889,7 +901,7 @@ static void vga_update_device_decodes(struct vga_device *vgadev,
__vga_put(vgadev, decodes_unlocked); __vga_put(vgadev, decodes_unlocked);
} }
/* change decodes counter */ /* Change decodes counter */
if (old_decodes & VGA_RSRC_LEGACY_MASK && if (old_decodes & VGA_RSRC_LEGACY_MASK &&
!(new_decodes & VGA_RSRC_LEGACY_MASK)) !(new_decodes & VGA_RSRC_LEGACY_MASK))
vga_decode_count--; vga_decode_count--;
@@ -913,16 +925,17 @@ static void __vga_set_legacy_decoding(struct pci_dev *pdev,
if (vgadev == NULL) if (vgadev == NULL)
goto bail; goto bail;
/* don't let userspace futz with kernel driver decodes */ /* Don't let userspace futz with kernel driver decodes */
if (userspace && vgadev->set_decode) if (userspace && vgadev->set_decode)
goto bail; goto bail;
/* update the device decodes + counter */ /* Update the device decodes + counter */
vga_update_device_decodes(vgadev, decodes); vga_update_device_decodes(vgadev, decodes);
/* XXX if somebody is going from "doesn't decode" to "decodes" state /*
* here, additional care must be taken as we may have pending owner * XXX If somebody is going from "doesn't decode" to "decodes"
* ship of non-legacy region ... * state here, additional care must be taken as we may have pending
* ownership of non-legacy region.
*/ */
bail: bail:
spin_unlock_irqrestore(&vga_lock, flags); spin_unlock_irqrestore(&vga_lock, flags);
@@ -930,10 +943,10 @@ bail:
/** /**
* vga_set_legacy_decoding * vga_set_legacy_decoding
* @pdev: pci device of the VGA card * @pdev: PCI device of the VGA card
* @decodes: bit mask of what legacy regions the card decodes * @decodes: bit mask of what legacy regions the card decodes
* *
* Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA
* Memory, both, or none. All cards default to both, the card driver (fbdev for * Memory, both, or none. All cards default to both, the card driver (fbdev for
* example) should tell the arbiter if it has disabled legacy decoding, so the * example) should tell the arbiter if it has disabled legacy decoding, so the
* card can be left out of the arbitration process (and can be safe to take * card can be left out of the arbitration process (and can be safe to take
@@ -947,25 +960,25 @@ EXPORT_SYMBOL(vga_set_legacy_decoding);
/** /**
* vga_client_register - register or unregister a VGA arbitration client * vga_client_register - register or unregister a VGA arbitration client
* @pdev: pci device of the VGA client * @pdev: PCI device of the VGA client
* @set_decode: vga decode change callback * @set_decode: VGA decode change callback
* *
* Clients have two callback mechanisms they can use. * Clients have two callback mechanisms they can use.
* *
* @set_decode callback: If a client can disable its GPU VGA resource, it * @set_decode callback: If a client can disable its GPU VGA resource, it
* will get a callback from this to set the encode/decode state. * will get a callback from this to set the encode/decode state.
* *
* Rationale: we cannot disable VGA decode resources unconditionally some single * Rationale: we cannot disable VGA decode resources unconditionally
* GPU laptops seem to require ACPI or BIOS access to the VGA registers to * because some single GPU laptops seem to require ACPI or BIOS access to
* control things like backlights etc. Hopefully newer multi-GPU laptops do * the VGA registers to control things like backlights etc. Hopefully newer
* something saner, and desktops won't have any special ACPI for this. The * multi-GPU laptops do something saner, and desktops won't have any
* driver will get a callback when VGA arbitration is first used by userspace * special ACPI for this. The driver will get a callback when VGA
* since some older X servers have issues. * arbitration is first used by userspace since some older X servers have
* issues.
* *
* This function does not check whether a client for @pdev has been registered * Does not check whether a client for @pdev has been registered already.
* already.
* *
* To unregister just call vga_client_unregister(). * To unregister, call vga_client_unregister().
* *
* Returns: 0 on success, -ENODEV on failure * Returns: 0 on success, -ENODEV on failure
*/ */
@@ -991,13 +1004,13 @@ EXPORT_SYMBOL(vga_client_register);
* *
* Semantics is: * Semantics is:
* *
* open : open user instance of the arbitrer. by default, it's * open : Open user instance of the arbiter. By default, it's
* attached to the default VGA device of the system. * attached to the default VGA device of the system.
* *
* close : close user instance, release locks * close : Close user instance, release locks
* *
* read : return a string indicating the status of the target. * read : Return a string indicating the status of the target.
* an IO state string is of the form {io,mem,io+mem,none}, * An IO state string is of the form {io,mem,io+mem,none},
* mc and ic are respectively mem and io lock counts (for * mc and ic are respectively mem and io lock counts (for
* debugging/diagnostic only). "decodes" indicate what the * debugging/diagnostic only). "decodes" indicate what the
* card currently decodes, "owns" indicates what is currently * card currently decodes, "owns" indicates what is currently
@@ -1011,7 +1024,7 @@ EXPORT_SYMBOL(vga_client_register);
* write : write a command to the arbiter. List of commands is: * write : write a command to the arbiter. List of commands is:
* *
* target <card_ID> : switch target to card <card_ID> (see below) * target <card_ID> : switch target to card <card_ID> (see below)
* lock <io_state> : acquires locks on target ("none" is invalid io_state) * lock <io_state> : acquire locks on target ("none" is invalid io_state)
* trylock <io_state> : non-blocking acquire locks on target * trylock <io_state> : non-blocking acquire locks on target
* unlock <io_state> : release locks on target * unlock <io_state> : release locks on target
* unlock all : release all locks on target held by this user * unlock all : release all locks on target held by this user
@@ -1028,23 +1041,21 @@ EXPORT_SYMBOL(vga_client_register);
* Note about locks: * Note about locks:
* *
* The driver keeps track of which user has what locks on which card. It * The driver keeps track of which user has what locks on which card. It
* supports stacking, like the kernel one. This complexifies the implementation * supports stacking, like the kernel one. This complicates the implementation
* a bit, but makes the arbiter more tolerant to userspace problems and able * a bit, but makes the arbiter more tolerant to userspace problems and able
* to properly cleanup in all cases when a process dies. * to properly cleanup in all cases when a process dies.
* Currently, a max of 16 cards simultaneously can have locks issued from * Currently, a max of 16 cards simultaneously can have locks issued from
* userspace for a given user (file descriptor instance) of the arbiter. * userspace for a given user (file descriptor instance) of the arbiter.
* *
* If the device is hot-unplugged, there is a hook inside the module to notify * If the device is hot-unplugged, there is a hook inside the module to notify
* they being added/removed in the system and automatically added/removed in * it being added/removed in the system and automatically added/removed in
* the arbiter. * the arbiter.
*/ */
#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS
#define PCI_INVALID_CARD ((struct pci_dev *)-1UL) #define PCI_INVALID_CARD ((struct pci_dev *)-1UL)
/* /* Each user has an array of these, tracking which cards have locks */
* Each user has an array of these, tracking which cards have locks
*/
struct vga_arb_user_card { struct vga_arb_user_card {
struct pci_dev *pdev; struct pci_dev *pdev;
unsigned int mem_cnt; unsigned int mem_cnt;
@@ -1063,9 +1074,8 @@ static DEFINE_SPINLOCK(vga_user_lock);
/* /*
* This function gets a string in the format: "PCI:domain:bus:dev.fn" and * Take a string in the format: "PCI:domain:bus:dev.fn" and return the
* returns the respective values. If the string is not in this format, * respective values. If the string is not in this format, return 0.
* it returns 0.
*/ */
static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
unsigned int *bus, unsigned int *devfn) unsigned int *bus, unsigned int *devfn)
@@ -1073,7 +1083,6 @@ static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
int n; int n;
unsigned int slot, func; unsigned int slot, func;
n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func);
if (n != 4) if (n != 4)
return 0; return 0;
@@ -1098,7 +1107,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
if (lbuf == NULL) if (lbuf == NULL)
return -ENOMEM; return -ENOMEM;
/* Protects vga_list */ /* Protect vga_list */
spin_lock_irqsave(&vga_lock, flags); spin_lock_irqsave(&vga_lock, flags);
/* If we are targeting the default, use it */ /* If we are targeting the default, use it */
@@ -1112,15 +1121,16 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
/* Find card vgadev structure */ /* Find card vgadev structure */
vgadev = vgadev_find(pdev); vgadev = vgadev_find(pdev);
if (vgadev == NULL) { if (vgadev == NULL) {
/* Wow, it's not in the list, that shouldn't happen, /*
* let's fix us up and return invalid card * Wow, it's not in the list, that shouldn't happen, let's
* fix us up and return invalid card.
*/ */
spin_unlock_irqrestore(&vga_lock, flags); spin_unlock_irqrestore(&vga_lock, flags);
len = sprintf(lbuf, "invalid"); len = sprintf(lbuf, "invalid");
goto done; goto done;
} }
/* Fill the buffer with infos */ /* Fill the buffer with info */
len = snprintf(lbuf, 1024, len = snprintf(lbuf, 1024,
"count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n",
vga_decode_count, pci_name(pdev), vga_decode_count, pci_name(pdev),
@@ -1166,7 +1176,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf,
if (copy_from_user(kbuf, buf, count)) if (copy_from_user(kbuf, buf, count))
return -EFAULT; return -EFAULT;
curr_pos = kbuf; curr_pos = kbuf;
kbuf[count] = '\0'; /* Just to make sure... */ kbuf[count] = '\0';
if (strncmp(curr_pos, "lock ", 5) == 0) { if (strncmp(curr_pos, "lock ", 5) == 0) {
curr_pos += 5; curr_pos += 5;
@@ -1191,7 +1201,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf,
vga_get_uninterruptible(pdev, io_state); vga_get_uninterruptible(pdev, io_state);
/* Update the client's locks lists... */ /* Update the client's locks lists */
for (i = 0; i < MAX_USER_CARDS; i++) { for (i = 0; i < MAX_USER_CARDS; i++) {
if (priv->cards[i].pdev == pdev) { if (priv->cards[i].pdev == pdev) {
if (io_state & VGA_RSRC_LEGACY_IO) if (io_state & VGA_RSRC_LEGACY_IO)
@@ -1308,7 +1318,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf,
curr_pos += 7; curr_pos += 7;
remaining -= 7; remaining -= 7;
pr_debug("client 0x%p called 'target'\n", priv); pr_debug("client 0x%p called 'target'\n", priv);
/* if target is default */ /* If target is default */
if (!strncmp(curr_pos, "default", 7)) if (!strncmp(curr_pos, "default", 7))
pdev = pci_dev_get(vga_default_device()); pdev = pci_dev_get(vga_default_device());
else { else {
@@ -1358,7 +1368,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user *buf,
vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n",
MAX_USER_CARDS); MAX_USER_CARDS);
pci_dev_put(pdev); pci_dev_put(pdev);
/* XXX: which value to return? */ /* XXX: Which value to return? */
ret_val = -ENOMEM; ret_val = -ENOMEM;
goto done; goto done;
} }
@@ -1419,13 +1429,12 @@ static int vga_arb_open(struct inode *inode, struct file *file)
list_add(&priv->list, &vga_user_list); list_add(&priv->list, &vga_user_list);
spin_unlock_irqrestore(&vga_user_lock, flags); spin_unlock_irqrestore(&vga_user_lock, flags);
/* Set the client' lists of locks */ /* Set the client's lists of locks */
priv->target = vga_default_device(); /* Maybe this is still null! */ priv->target = vga_default_device(); /* Maybe this is still null! */
priv->cards[0].pdev = priv->target; priv->cards[0].pdev = priv->target;
priv->cards[0].io_cnt = 0; priv->cards[0].io_cnt = 0;
priv->cards[0].mem_cnt = 0; priv->cards[0].mem_cnt = 0;
return 0; return 0;
} }
@@ -1459,8 +1468,8 @@ static int vga_arb_release(struct inode *inode, struct file *file)
} }
/* /*
* callback any registered clients to let them know we have a * Callback any registered clients to let them know we have a change in VGA
* change in VGA cards * cards.
*/ */
static void vga_arbiter_notify_clients(void) static void vga_arbiter_notify_clients(void)
{ {
@@ -1494,9 +1503,11 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
vgaarb_dbg(dev, "%s\n", __func__); vgaarb_dbg(dev, "%s\n", __func__);
/* For now we're only intereted in devices added and removed. I didn't /*
* test this thing here, so someone needs to double check for the * For now, we're only interested in devices added and removed.
* cases of hotplugable vga cards. */ * I didn't test this thing here, so someone needs to double check
* for the cases of hot-pluggable VGA cards.
*/
if (action == BUS_NOTIFY_ADD_DEVICE) if (action == BUS_NOTIFY_ADD_DEVICE)
notify = vga_arbiter_add_pci_device(pdev); notify = vga_arbiter_add_pci_device(pdev);
else if (action == BUS_NOTIFY_DEL_DEVICE) else if (action == BUS_NOTIFY_DEL_DEVICE)
@@ -1535,8 +1546,7 @@ static int __init vga_arb_device_init(void)
bus_register_notifier(&pci_bus_type, &pci_notifier); bus_register_notifier(&pci_bus_type, &pci_notifier);
/* We add all PCI devices satisfying VGA class in the arbiter by /* Add all VGA class PCI devices by default */
* default */
pdev = NULL; pdev = NULL;
while ((pdev = while ((pdev =
pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,