Commit ff36baf8 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/vmwgfx: Drop svga_lock 



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: default avatarDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: default avatarZack Rusin <zackr@vmware.com>
Reviewed-by: default avatarRoland Scheidegger <sroland@vmware.com>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Roland Scheidegger <sroland@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201211162942.3399050-1-daniel.vetter@ffwll.ch
parent 87969bcd

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

+1 −9
Original line number Diff line number Diff line
@@ -727,7 +727,6 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id) 
	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) {
@@ -1193,12 +1192,10 @@ 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);

}



/**
@@ -1224,14 +1221,12 @@ 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);

}



/**
@@ -1258,17 +1253,14 @@ void vmw_svga_disable(struct vmw_private *dev_priv) 
	 */

	vmw_kms_lost_device(&dev_priv->drm);

	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);

}

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

+0 −1
Original line number Diff line number Diff line
@@ -584,7 +584,6 @@ struct vmw_private { 
	struct mutex binding_mutex;



	bool enable_fb;

	spinlock_t svga_lock;



	/**

	 * PM management.