This isn't actually protecting anything becuase: - when running, ttm_resource_manager->use_type is protected through vmw_private->reservation_semaphore against concurrent execbuf or well anything else that might evict or reserve buffers - during suspend/resume there's nothing else running, hence vmw_pm_freeze and vmw_pm_restore do not need to take the same lock. - this also holds for the SVGA_REG_ENABLE register write
Hence it is safe to just remove that spinlock.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: VMware Graphics linux-graphics-maintainer@vmware.com Cc: Roland Scheidegger sroland@vmware.com --- drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 10 +--------- drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 1 - 2 files changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c index 0008be02d31c..204f7a1830f0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c @@ -672,7 +672,6 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset) spin_lock_init(&dev_priv->hw_lock); spin_lock_init(&dev_priv->waiter_lock); spin_lock_init(&dev_priv->cap_lock); - spin_lock_init(&dev_priv->svga_lock); spin_lock_init(&dev_priv->cursor_lock);
for (i = vmw_res_context; i < vmw_res_max; ++i) { @@ -1189,12 +1188,10 @@ static void __vmw_svga_enable(struct vmw_private *dev_priv) { struct ttm_resource_manager *man = ttm_manager_type(&dev_priv->bdev, TTM_PL_VRAM);
- spin_lock(&dev_priv->svga_lock); if (!ttm_resource_manager_used(man)) { vmw_write(dev_priv, SVGA_REG_ENABLE, SVGA_REG_ENABLE); ttm_resource_manager_set_used(man, true); } - spin_unlock(&dev_priv->svga_lock); }
/** @@ -1220,14 +1217,12 @@ static void __vmw_svga_disable(struct vmw_private *dev_priv) { struct ttm_resource_manager *man = ttm_manager_type(&dev_priv->bdev, TTM_PL_VRAM);
- spin_lock(&dev_priv->svga_lock); if (ttm_resource_manager_used(man)) { ttm_resource_manager_set_used(man, false); vmw_write(dev_priv, SVGA_REG_ENABLE, SVGA_REG_ENABLE_HIDE | SVGA_REG_ENABLE_ENABLE); } - spin_unlock(&dev_priv->svga_lock); }
/** @@ -1254,17 +1249,14 @@ void vmw_svga_disable(struct vmw_private *dev_priv) */ vmw_kms_lost_device(dev_priv->dev); ttm_write_lock(&dev_priv->reservation_sem, false); - spin_lock(&dev_priv->svga_lock); if (ttm_resource_manager_used(man)) { ttm_resource_manager_set_used(man, false); - spin_unlock(&dev_priv->svga_lock); if (ttm_resource_manager_evict_all(&dev_priv->bdev, man)) DRM_ERROR("Failed evicting VRAM buffers.\n"); vmw_write(dev_priv, SVGA_REG_ENABLE, SVGA_REG_ENABLE_HIDE | SVGA_REG_ENABLE_ENABLE); - } else - spin_unlock(&dev_priv->svga_lock); + } ttm_write_unlock(&dev_priv->reservation_sem); }
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h index 5b9a28157dd3..715f2bfee08a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h @@ -596,7 +596,6 @@ struct vmw_private {
bool stealth; bool enable_fb; - spinlock_t svga_lock;
/** * PM management.
Other way round is a bit inconsistent (but not buggy in any kind). This is prep work so that ttm_resource_manager_set_used can assert that the resource manager is empty.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: VMware Graphics linux-graphics-maintainer@vmware.com Cc: Roland Scheidegger sroland@vmware.com --- drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c index 204f7a1830f0..0d074c432152 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c @@ -1250,9 +1250,9 @@ void vmw_svga_disable(struct vmw_private *dev_priv) vmw_kms_lost_device(dev_priv->dev); ttm_write_lock(&dev_priv->reservation_sem, false); if (ttm_resource_manager_used(man)) { - ttm_resource_manager_set_used(man, false); if (ttm_resource_manager_evict_all(&dev_priv->bdev, man)) DRM_ERROR("Failed evicting VRAM buffers.\n"); + ttm_resource_manager_set_used(man, false); vmw_write(dev_priv, SVGA_REG_ENABLE, SVGA_REG_ENABLE_HIDE | SVGA_REG_ENABLE_ENABLE);
ttm_resource_manager->use_type is only used for runtime changes by vmwgfx. I think ideally we'd push this functionality into drivers - ttm itself does not provide any locking to guarantee this is safe, so the only way this can work at runtime is if the driver does provide additional guarantees. vwmgfx does that through the vmw_private->reservation_sem. Therefore supporting this feature in shared code feels a bit misplaced.
As a first step add a WARN_ON to make sure the resource manager is empty. This is just to make sure I actually understand correctly what vmwgfx is doing, and to make sure an eventual subsequent refactor doesn't break anything.
This check should also be useful for other drivers, to make sure they haven't leaked anything.
Reviewed-by: Christian König christian.koenig@amd.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Christian Koenig christian.koenig@amd.com Cc: Huang Rui ray.huang@amd.com --- include/drm/ttm/ttm_resource.h | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h index f48a70d39ac5..789ec477b607 100644 --- a/include/drm/ttm/ttm_resource.h +++ b/include/drm/ttm/ttm_resource.h @@ -191,6 +191,10 @@ struct ttm_resource { static inline void ttm_resource_manager_set_used(struct ttm_resource_manager *man, bool used) { + int i; + + for (i = 0; i < TTM_MAX_BO_PRIORITY; i++) + WARN_ON(!list_empty(&man->lru[i])); man->use_type = used; }
Hi Roland,
Hopefully you had a nice start into the new year! Ping for some review/testing on this series.
Thanks, Daniel
On Fri, Dec 11, 2020 at 5:29 PM Daniel Vetter daniel.vetter@ffwll.ch wrote:
Hi,
looking at it, seems alright. Not sure why the lock was supposedly needed, maybe it was at some point (it seems like all usage of this lock was introduced way back in 2015, commit 153b3d5b037ee).
For the series: Reviewed-by: Roland Scheidegger sroland@vmware.com
Roland
Am 12.01.21 um 09:49 schrieb Daniel Vetter:
On Thu, Jan 14, 2021 at 04:31:09PM +0100, Roland Scheidegger wrote:
Series merged, thanks for taking a look. -Daniel
dri-devel@lists.freedesktop.org
-
Daniel Vetter -
Daniel Vetter -
Roland Scheidegger -
Zack Rusin