On Tue, Jul 08, 2014 at 12:15:31AM +0200, Jiri Kosina wrote: > On Mon, 7 Jul 2014, Chris Wilson wrote: > > > > > this patch on top of v3.16-rc3-62-gd92a333 makes the resume from ram > > > > regression go away on my machine: > > > > > > Hm, we could conditionalize this hack on IS_G4X ... Chris, thoughts? > > > > As different machines favour different w/a, I think the issue is mostly > > timing related. It could be sequence of register writes, but we tried > > different orders early on. The next experiment I guess would be to > > insert small delays between each write to see if that helps. Or to write > > each register twice. > > I actually tried to introduce rather large delays between individual > I915_WRITE() calls in the ring initialization sequence a couple weeks ago > already, but it resulted in complete machine lockup (which is worse than > my usual symptoms) during resume. Therefore I probably lack the knowledge > of internal workings of the HW that would allow me to guess what the > reasonable timeout value should be. Have you used msleep or udelay? The latter just spins the cpu and might be less dangerous. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
