[PATCH 2/2] vga switch: hi my name is race condition

From: Dave Airlie
Date: Wed Feb 24 2010 - 23:44:40 EST

From: Dave Airlie <airlied@xxxxxxxx>

This adds a delayed switch mode, and also changes the debugfs file
to accept different parameters.
It also adds switch blocking by the drm if any devices are in use

echo:
DIS - immediate change to discrete
IGD - immediate change to IGD
DDIS - delayed change to discrete
DIGD - delayed change to IGD
ON - turn on not in use
OFF - turn off not in use

no more PCI IDs.
---
drivers/gpu/drm/i915/i915_dma.c | 16 ++++-
drivers/gpu/drm/nouveau/nouveau_state.c | 14 +++-
drivers/gpu/drm/radeon/r600_audio.c | 3 +
drivers/gpu/drm/radeon/radeon.h | 2 +
drivers/gpu/drm/radeon/radeon_atpx_handler.c | 2 +
drivers/gpu/drm/radeon/radeon_device.c | 26 ++++++-
drivers/gpu/drm/radeon/radeon_kms.c | 3 +
drivers/gpu/vga/vga_switcheroo.c | 108 ++++++++++++++++++++++---
include/linux/vga_switcheroo.h | 5 +-
9 files changed, 162 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 2e70292..3fb32fd 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1202,6 +1202,17 @@ static void i915_switcheroo_set_state(struct pci_dev *pdev, enum vga_switcheroo_
}
}

+static bool i915_switcheroo_can_switch(struct pci_dev *pdev)
+{
+ struct drm_device *dev = pci_get_drvdata(pdev);
+ bool can_switch;
+
+ spin_lock(&dev->count_lock);
+ can_switch = (dev->open_count == 0);
+ spin_unlock(&dev->count_lock);
+ return can_switch;
+}
+
static int i915_load_modeset_init(struct drm_device *dev,
unsigned long prealloc_start,
unsigned long prealloc_size,
@@ -1271,7 +1282,9 @@ static int i915_load_modeset_init(struct drm_device *dev,
if (ret)
goto destroy_ringbuffer;

- ret = vga_switcheroo_register_client(dev->pdev, i915_switcheroo_set_state);
+ ret = vga_switcheroo_register_client(dev->pdev,
+ i915_switcheroo_set_state,
+ i915_switcheroo_can_switch);
if (ret)
goto destroy_ringbuffer;

@@ -1624,6 +1637,7 @@ void i915_driver_lastclose(struct drm_device * dev)

if (!dev_priv || drm_core_check_feature(dev, DRIVER_MODESET)) {
drm_fb_helper_restore();
+ vga_switcheroo_process_delayed_switch();
return;
}

diff --git a/drivers/gpu/drm/nouveau/nouveau_state.c b/drivers/gpu/drm/nouveau/nouveau_state.c
index 940fdd3..afddcca 100644
--- a/drivers/gpu/drm/nouveau/nouveau_state.c
+++ b/drivers/gpu/drm/nouveau/nouveau_state.c
@@ -377,6 +377,17 @@ static void nouveau_switcheroo_set_state (struct pci_dev *pdev,
}
}

+static bool nouveau_switcheroo_can_switch(struct pci_dev *pdev)
+{
+ struct drm_device *dev = pci_get_drvdata(pdev);
+ bool can_switch;
+
+ spin_lock(&dev->count_lock);
+ can_switch = (dev->open_count == 0);
+ spin_unlock(&dev->count_lock);
+ return can_switch;
+}
+
int
nouveau_card_init(struct drm_device *dev)
{
@@ -390,7 +401,8 @@ nouveau_card_init(struct drm_device *dev)
return 0;

vga_client_register(dev->pdev, dev, NULL, nouveau_vga_set_decode);
- vga_switcheroo_register_client(dev->pdev, nouveau_switcheroo_set_state);
+ vga_switcheroo_register_client(dev->pdev, nouveau_switcheroo_set_state,
+ nouveau_switcheroo_can_switch);

/* Initialise internal driver API hooks */
ret = nouveau_init_engine_ptrs(dev);
diff --git a/drivers/gpu/drm/radeon/r600_audio.c b/drivers/gpu/drm/radeon/r600_audio.c
index 99e2c38..e880cd8 100644
--- a/drivers/gpu/drm/radeon/r600_audio.c
+++ b/drivers/gpu/drm/radeon/r600_audio.c
@@ -163,6 +163,9 @@ int r600_audio_init(struct radeon_device *rdev)
rdev->audio_status_bits = 0;
rdev->audio_category_code = 0;

+ if (!radeon_audio)
+ return 0;
+
setup_timer(
&rdev->audio_timer,
r600_audio_update_hdmi,
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index f7df1a7..694c453 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -829,6 +829,8 @@ struct radeon_device {
int audio_bits_per_sample;
uint8_t audio_status_bits;
uint8_t audio_category_code;
+
+ bool powered_down;
};

int radeon_device_init(struct radeon_device *rdev,
diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
index 808d980..c614794 100644
--- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c
+++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
@@ -3,6 +3,8 @@
* Author : Dave Airlie <airlied@xxxxxxxxxx>
*
* Licensed under GPLv2
+ *
+ * ATPX support for both Intel/ATI
*/

#include <linux/vga_switcheroo.h>
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 3ad4aba..a9b87b4 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -620,16 +620,33 @@ void radeon_check_arguments(struct radeon_device *rdev)
static void radeon_switcheroo_set_state(struct pci_dev *pdev, enum vga_switcheroo_state state)
{
struct drm_device *dev = pci_get_drvdata(pdev);
+ struct radeon_device *rdev = dev->dev_private;
pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
if (state == VGA_SWITCHEROO_ON) {
printk(KERN_ERR "VGA switched radeon on\n");
radeon_resume_kms(dev);
+ r600_audio_init(rdev);
} else {
printk(KERN_ERR "VGA switched radeon off\n");
+ r600_audio_fini(rdev);
radeon_suspend_kms(dev, pmm);
}
+ /* don't suspend or resume card normally */
+ rdev->powered_down = true;
+}
+
+static bool radeon_switcheroo_can_switch(struct pci_dev *pdev)
+{
+ struct drm_device *dev = pci_get_drvdata(pdev);
+ bool can_switch;
+
+ spin_lock(&dev->count_lock);
+ can_switch = (dev->open_count == 0);
+ spin_unlock(&dev->count_lock);
+ return can_switch;
}

+
int radeon_device_init(struct radeon_device *rdev,
struct drm_device *ddev,
struct pci_dev *pdev,
@@ -709,7 +726,9 @@ int radeon_device_init(struct radeon_device *rdev,
/* this will fail for cards that aren't VGA class devices, just
* ignore it */
vga_client_register(rdev->pdev, rdev, NULL, radeon_vga_set_decode);
- vga_switcheroo_register_client(rdev->pdev, radeon_switcheroo_set_state);
+ vga_switcheroo_register_client(rdev->pdev,
+ radeon_switcheroo_set_state,
+ radeon_switcheroo_can_switch);

r = radeon_init(rdev);
if (r)
@@ -764,6 +783,8 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state)
}
rdev = dev->dev_private;

+ if (rdev->powered_down)
+ return 0;
/* unpin the front buffers */
list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
struct radeon_framebuffer *rfb = to_radeon_framebuffer(crtc->fb);
@@ -809,6 +830,9 @@ int radeon_resume_kms(struct drm_device *dev)
{
struct radeon_device *rdev = dev->dev_private;

+ if (rdev->powered_down)
+ return 0;
+
acquire_console_sem();
pci_set_power_state(dev->pdev, PCI_D0);
pci_restore_state(dev->pdev);
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index f23b056..5db7af6 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -30,6 +30,8 @@
#include "radeon.h"
#include "radeon_drm.h"

+#include <linux/vga_switcheroo.h>
+
int radeon_driver_unload_kms(struct drm_device *dev)
{
struct radeon_device *rdev = dev->dev_private;
@@ -136,6 +138,7 @@ int radeon_driver_firstopen_kms(struct drm_device *dev)

void radeon_driver_lastclose_kms(struct drm_device *dev)
{
+ vga_switcheroo_process_delayed_switch();
}

int radeon_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index c4779ab..6b4781a 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -36,21 +36,21 @@ struct vga_switcheroo_client {
struct pci_dev *pdev;
struct fb_info *fb_info;
int pwr_state;
- /* TODO callbacks */
void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state);
- /* TODO callbacks */
- void (*switch_check)(struct pci_dev *pdev);
+ bool (*can_switch)(struct pci_dev *pdev);
};

struct vgasr_priv {

bool active;
+ bool delayed_switch_active;
+ enum vga_switcheroo_client_id delayed_client_id;

struct dentry *debugfs_root;
struct dentry *switch_file;

enum vga_switcheroo_method method;
- int active_client;
+ enum vga_switcheroo_client_id active_client;

int registered_clients;
struct vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
@@ -164,7 +164,8 @@ void vga_switcheroo_unregister_handler(void)
EXPORT_SYMBOL(vga_switcheroo_unregister_handler);

int vga_switcheroo_register_client(struct pci_dev *pdev,
- void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state))
+ void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state),
+ bool (*can_switch)(struct pci_dev *pdev))
{
enum vga_switcheroo_client_id client_id;

@@ -178,6 +179,7 @@ int vga_switcheroo_register_client(struct pci_dev *pdev,
vgasr_priv.clients[client_id].pwr_state = VGA_SWITCHEROO_ON;
vgasr_priv.clients[client_id].pdev = pdev;
vgasr_priv.clients[client_id].set_gpu_state = set_gpu_state;
+ vgasr_priv.clients[client_id].can_switch = can_switch;
if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
vgasr_priv.active_client = client_id;

@@ -305,8 +307,10 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char pci_id[64];
- char *pdev_name;
+ const char *pdev_name;
int i, ret;
+ enum vga_switcheroo_client_id client_id = -1;
+ bool delay = false, can_switch;

if (cnt > 63)
cnt = 63;
@@ -314,6 +318,7 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
if (copy_from_user(pci_id, ubuf, cnt))
return -EFAULT;

+
/* pwr off the device not in use */
if (strncmp(pci_id, "OFF", 3) == 0) {
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
@@ -336,17 +341,60 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
}
goto out;
}
- /* switch devices */
+
+ /* request a delayed switch - test can we switch now */
+ if (strncmp(pci_id, "DIGD", 4) == 0) {
+ client_id = VGA_SWITCHEROO_IGD;
+ delay = true;
+ }
+
+ if (strncmp(pci_id, "DDIS", 4) == 0) {
+ client_id = VGA_SWITCHEROO_DIS;
+ delay = true;
+ }
+
+ if (strncmp(pci_id, "IGD", 3) == 0) {
+ client_id = VGA_SWITCHEROO_IGD;
+ }
+
+ if (strncmp(pci_id, "DIS", 3) == 0) {
+ client_id = VGA_SWITCHEROO_DIS;
+ }
+
+ if (client_id == -1)
+ goto out;
+
+ vgasr_priv.delayed_switch_active = false;
+ /* okay we want a switch - test if devices are willing to switch */
+ can_switch = true;
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
- pdev_name = pci_name(vgasr_priv.clients[i].pdev);
- if (strncmp(pci_id, pdev_name, strlen(pdev_name)) == 0) {
- printk("switching to %d %s\n", i, pdev_name);
- ret = vga_switchto(i);
- if (ret)
- printk("switching failed %d\n", ret);
+ can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
+ if (can_switch == false) {
+ printk(KERN_ERR "Client %d refused switch\n", i);
break;
}
}
+
+ if (can_switch == false && delay == false)
+ goto out;
+
+ if (can_switch == true) {
+ pdev_name = pci_name(vgasr_priv.clients[client_id].pdev);
+ printk("switching to %s\n", pdev_name);
+ ret = vga_switchto(client_id);
+ if (ret)
+ printk("switching failed %d\n", ret);
+ } else {
+ printk(KERN_ERR "setting delayed switch to client %d\n", client_id);
+ vgasr_priv.delayed_switch_active = true;
+ vgasr_priv.delayed_client_id = client_id;
+
+ /* we should at least power up the card to
+ make the switch faster */
+ if (vgasr_priv.clients[client_id].pwr_state == VGA_SWITCHEROO_OFF)
+ vga_switchon(client_id);
+ }
+
out:
return cnt;
}
@@ -395,3 +443,37 @@ fail:
vga_switcheroo_debugfs_fini(priv);
return -1;
}
+
+int vga_switcheroo_process_delayed_switch(void)
+{
+ const char *pdev_name;
+ bool can_switch = true;
+ int i;
+ int ret;
+
+ if (!vgasr_priv.delayed_switch_active)
+ return -EINVAL;
+
+ printk(KERN_ERR "processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
+
+ for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
+ can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
+ if (can_switch == false) {
+ printk(KERN_ERR "Client %d refused switch\n", i);
+ break;
+ }
+ }
+
+ if (can_switch == false)
+ return -EINVAL;
+
+ pdev_name = pci_name(vgasr_priv.clients[vgasr_priv.delayed_client_id].pdev);
+ printk("delayed switching to %s\n", pdev_name);
+ ret = vga_switchto(vgasr_priv.delayed_client_id);
+ if (ret)
+ printk("switching failed %d\n", ret);
+
+ vgasr_priv.delayed_switch_active = false;
+ return 0;
+}
+EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index 694cfc5..fc30f82 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -29,7 +29,8 @@ enum vga_switcheroo_client_id {

void vga_switcheroo_unregister_client(struct pci_dev *dev);
int vga_switcheroo_register_client(struct pci_dev *dev,
- void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state));
+ void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state),
+ bool (*can_switch)(struct pci_dev *dev));

void vga_switcheroo_client_fb_set(struct pci_dev *dev,
struct fb_info *info);
@@ -45,3 +46,5 @@ struct vga_switcheroo_handler {

int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler);
void vga_switcheroo_unregister_handler(void);
+
+int vga_switcheroo_process_delayed_switch(void);
--
1.6.5.2

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