Re: [PATCH 4/4] drm/radeon: unpin cursor BOs before suspend

["Michel Dänzer" <michel@daenzer.net>]

[ Dropping stable@vger.kernel.org from Cc; the patch will be picked up
for stable after it lands in Linus' tree ]

On 03.07.2015 08:54, Grigori Goronzy wrote:
> Everything is evicted from VRAM before suspend, so we need to make
> sure all BOs are unpinned and re-pinned after resume. Fixes broken
> mouse cursor after resume introduced by commit b9729b17.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100541
> Cc: stable@vger.kernel.org
> Signed-off-by: Grigori Goronzy <greg@chown.ath.cx>
> ---
>  drivers/gpu/drm/radeon/radeon_device.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> index 14deeae..dddd5df 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -1578,6 +1578,20 @@ int radeon_suspend_kms(struct drm_device *dev, bool suspend, bool fbcon)
>  		drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF);
>  	}
>  
> +	/* unpin cursors */
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
> +
> +		if (radeon_crtc->cursor_bo) {
> +			struct radeon_bo *robj = gem_to_radeon_bo(radeon_crtc->cursor_bo);
> +			r = radeon_bo_reserve(robj, false);
> +			if (r == 0) {
> +				radeon_bo_unpin(robj);
> +				radeon_bo_unreserve(robj);
> +			}
> +		}
> +	}
> +
>  	/* unpin the front buffers */
>  	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
>  		struct radeon_framebuffer *rfb = to_radeon_framebuffer(crtc->primary->fb);
> 

This could be done in the same loop as the front buffers.

On resume, the cursor BO is currently pinned again by
radeon_cursor_reset -> radeon_set_cursor. However, radeon_cursor_reset
is also called when changing the video mode, in which case it causes the
cursor BO pin count to increase by 1 for each CRTC using it. Presumably,
the mouse cursor would end up broken again on suspend/resume after that
for you.

We need a solution which pins the BO again on resume but doesn't
increase the pin count during a mode change. I'm not sure right now what
the best way is to achieve that, I'll think about it more later.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer