[PATCH 1/2] drm/nouveau: Add lock on drm_helper_resume_force_mode

[PATCH 1/2] drm/nouveau: Add lock on drm_helper_resume_force_mode

[Peter Huewe]

mode_config should be locked when calling drm_helper_resume_force_mode.
This patch adds the lock, similar to #927a2f119.

Cc: stable@kernel.org
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/gpu/drm/nouveau/nouveau_drv.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.c b/drivers/gpu/drm/nouveau/nouveau_drv.c
index 4f2030b..6260abe 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.c
@@ -375,7 +375,9 @@ nouveau_pci_resume(struct pci_dev *pdev)
 		nv_crtc->lut.depth = 0;
 	}
 
+	mutex_lock(&dev->mode_config.mutex);
 	drm_helper_resume_force_mode(dev);
+	mutex_unlock(&dev->mode_config.mutex);
 
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
-- 
1.7.3.4

[PATCH 2/2] drm/radeon: Add lock on drm_helper_resume_force_mode

[Peter Huewe]

mode_config should be locked when calling drm_helper_resume_force_mode.
This patch adds the lock, similar to #927a2f119.

Cc: stable@kernel.org
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/gpu/drm/radeon/radeon_device.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index ea7df16..d287f23 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -973,7 +973,9 @@ int radeon_resume_kms(struct drm_device *dev)
 	/* reset hpd state */
 	radeon_hpd_init(rdev);
 	/* blat the mode back in */
+	mutex_lock(&dev->mode_config.mutex);
 	drm_helper_resume_force_mode(dev);
+	mutex_unlock(&dev->mode_config.mutex);
 	/* turn on display hw */
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
-- 
1.7.3.4

Re: [PATCH 1/2] drm/nouveau: Add lock on drm_helper_resume_force_mode

[Jonathan Nieder]

Hi,

Peter Huewe wrote:

> mode_config should be locked when calling drm_helper_resume_force_mode.
> This patch adds the lock, similar to #927a2f119.

Does this fix a problem that has been observed in the wild, or only a
theoretical one?

Curious,
Jonathan

Re: [PATCH 1/2] drm/nouveau: Add lock on drm_helper_resume_force_mode

[Peter Hüwe]

Am Samstag 14 April 2012, 02:52:19 schrieb Jonathan Nieder:
> Hi,
> 
> Peter Huewe wrote:
> > mode_config should be locked when calling drm_helper_resume_force_mode.
> > This patch adds the lock, similar to #927a2f119.
> 
> Does this fix a problem that has been observed in the wild, or only a
> theoretical one?
> 
> Curious,
> Jonathan

Only theoretical ;)
Since all other drivers always lock around drm_helper_resume_force_mode I 
guessed this is good practice.

And since problem area is quite similar to the one mentioned in #927a2f119 / 
234f78a683e 
http://git.kernel.org/?p=linux/kernel/git/stable/linux-
stable.git;a=commit;h=234f78a683e30d6d4628846fde4a822c0e385529
the bug might happen in the wild.


Thanks,
Peter