[Intel-gfx] [PATCH] drm/i915: don't update the dri1 breadcrumb with modesetting

[Chris Wilson]

On Tue, Dec 10, 2013 at 01:24:01PM +0100, Daniel Vetter wrote:
> The update is horribly racy since it doesn't protect at all against
> concurrent closing of the master fd. And it can't really since that
> requires us to grab a mutex.
> 
> Instead of jumping through hoops and offloading this to a worker
> thread just block this bit of code for the modesetting driver.
> 
> Reported-by: Eugene Shatokhin <eugene.shatokhin at rosalab.ru>
> Cc: Eugene Shatokhin <eugene.shatokhin at rosalab.ru>
> Cc: stable at vger.kernel.org
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

We should also not be calling update_dri1_breadcrumb unless we have a
USER_INTERRUPT. The other updates to the breadcrumb hws index do not
appear to be serialised by anything other than polling.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre