Re: [PATCH 00/43] Execlists v5

Daniel Vetter
2014-07-25T08:35:02Z

Please format mails to a width of 75 chars or so. Decent mailers should do
that for you when hitting send.

On Thu, Jul 24, 2014 at 05:04:08PM +0100, Thomas Daniel wrote:
> From: Thomas Daniel <thomas.daniel@intel.com>
> The previous comment about the WAs still applies. I reproduce it here
> for completeness:
>
> "One other caveat I have noticed is that many WAs in
> gen8_init_clock_gating (those that affect registers that now exist
> per-context) can get lost in the render default context. The reason is,
> in Execlists, a context is saved as soon as head = tail (with
> MI_SET_CONTEXT, however, the context wouldn't be saved until you tried
> to restore a different context). As we are sending the golden state
> batchbuffer to the render ring as soon as the rings are initialized, we
> are effectively saving the default context before gen8_init_clock_gating
> has an opportunity to set the WAs. I haven't noticed any ill-effect from
> this (yet) but it would be a good idea to move the WAs somewhere else
> (ring init looks like a good place). I believe there is already work in
> progress to create a new WA architecture, so this can be tackled there."

This sounds like the w/a test patch to compare wa reg state after system
s/r, runtime pm, gpu reset and driver reload should also have a test for
multiple contexts. I'll add it to the wishlist.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch