2013/8/19 Ben Widawsky <ben@xxxxxxxxxxxx>: > On Mon, Aug 19, 2013 at 04:01:13PM -0300, Paulo Zanoni wrote: >> From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> >> >> If LCPLL is disabled, there's a chance we might be in package C8 state >> or deeper, and we'll get a hard hang when restoring LCPLL (also, a red >> led lights up on my motherboard). So grab the force_wake, which will >> get us out of RC6 and, as a consequence, out of PC8+ (since we need >> RC6 to get into PC8+). >> >> v2: Call the correct force_wake interface. >> >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> > > Hi Paulo. As I recall, the steps in the bspec are laid out exactly so we > don't have to call forcewake. I think the explanation sounds a little > fishy. Well, we seem to do exactly what BSpec says we need to do and we still get the hard machine hang if we're in PC8 while restoring from LCPLL. > > Specifically, I thought D_COMP COMP_FORCE + waiting for PLL lock was > sufficient. Why? I don't see D_COMP documentation anywhere or any text that leads me to believe that. The spec just says "enable these bits, disable these others" without any explanations on what we're really doing. > If it's not, I worry you're papering over another bug, or > incorrect bspec sequence. > > Not opposed to the patch in the meanwhile, but it just feels a little > unsafe to me. I'll send some emails requesting for clarification. We certainly can't merge PC8 without this patch or an equivalent fix. > > -- > Ben Widawsky, Intel Open Source Technology Center -- Paulo Zanoni _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
