On Thu, 29 Mar 2012 21:25:49 +0200 Daniel Vetter <daniel at ffwll.ch> wrote: > On Sun, Mar 18, 2012 at 01:39:49PM -0700, Ben Widawsky wrote: > > From http://intellinuxgraphics.org/documentation/SNB/IHD_OS_Vol1_Part3.pdf > > > > [DevSNB] If Flush TLB invalidation Mode is enabled it?s the driver?s > > responsibility to invalidate the TLBs at least once after the previous > > context switch after any GTT mappings changed (including new GTT > > entries). This can be done by a pipelined PIPE_CONTROL with TLB inv bit > > set immediately before MI_SET_CONTEXT. > > > > Signed-off-by: Ben Widawsky <ben at bwidawsk.net> > > Hm, I've beend decently confused about the meaning of > GFX_TLB_INVALIDATE_ALWAYS - it actually means that we flush tlbs on every > full flush (i.e. always) when it's reset. And we don't set this so this > workaround is pretty much just informational. I'm hence wondering whether > a big comment wouldn't be better? > > -Daniel It's probably not much difference in terms of LOC with the plus that the "comment" turns into correctly functioning code if we flip the bit. Just from a quick glance at code though, it seems we don't explicitly touch this bit for GEN6. Which was probably why I did it in the first place. if (IS_GEN7(dev)) I915_WRITE(GFX_MODE_GEN7, GFX_MODE_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) | GFX_MODE_ENABLE(GFX_REPLAY_MODE)); Anyway, I really don't care enough to argue, but I like the way it is, and it's been tested the way it is; call the ball. Ben
