> -----Original Message----- > From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of Daniel > Vetter > Sent: Wednesday, June 18, 2014 8:51 PM > To: Mateo Lozano, Oscar > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/8] drm/i915: Get rid of the synchronous flag > in switch_mm > > On Wed, Jun 18, 2014 at 05:15:35PM +0100, oscar.mateo@xxxxxxxxx wrote: > > From: Oscar Mateo <oscar.mateo@xxxxxxxxx> > > > > As a first step, split switch_mm into two different functions: > > sync_switch_mm (currently used by ppgtt_enable) and switch_mm (used by > > the outside world). > > > > Signed-off-by: Oscar Mateo <oscar.mateo@xxxxxxxxx> > > I guess that jira task description was a bit unclear - removing the bool > synchronous argument isn't the goal itself. The idea was to rework the gpu > reset sequence so that it matches the same sequence we use at driver load > and so can use the same code. This patch removes the bool synchronous, but > the logical split with two different ways to load ppgtt is still there. No, I realized I didn´t really do anything, but I saw the possibility of saving one special casing in Execlists and I jumped for it, forgetting about the JIRA task (psychological fixation, I guess) Anyway, I was going to ask for more details on the JIRA... > The reason for aiming as hard as possible to use the exact same code for > driver load, gpu reset and runtime pm/system resume is that we've simply > seen too many bugs due to slight variations and unintended omissions. > > If for some really odd reason this is impossible (e.g. when the gpu needs a > special dance when coming out of reset) then we need a giant comment > explaining the magic. But without such a clear reason the goal should always > be to have just 1 single autorative piece of code for a given state transition. Ok. How about this: on ring init, I manually set the Aliasing PPGTT and the default context object synchronously via MMIO writes (the Aliasing PPGTT via the ppgtt->sync_switch_mm() and the default context directly using the CCID). I assume that, whenever we are in ring init, the GPU is sufficiently idle to manually frob all the required registers. That way, I get rid of i915_gem_context_enable() completely and I don´t have to do any special casing at all. Ring commands (PPGTT switch and MI_SET_CONTEXT) are then left completely for the normal do_switch(). What do you think? -- Oscar _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
