[Intel-gfx] [PATCH v2] drm/i915: Make IRQ reset and postinstall multi-gt aware

[Andi Shyti]

Hi Tvrtko,

(I forgot to CC Daniele)

On Thu, Apr 13, 2023 at 11:41:28AM +0100, Tvrtko Ursulin wrote:
> 
> On 13/04/2023 10:20, Andi Shyti wrote:
> > From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > 
> > In multitile systems IRQ need to be reset and enabled per GT.
> > 
> > Although in MTL the GUnit misc interrupts register set are
> > available only in GT-0, we need to loop through all the GT's
> > in order to initialize the media engine which lies on a different
> > GT.
> > 
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
> > ---
> > Hi,
> > 
> > proposing again this patch, apparently GuC needs this patch to
> > initialize the media GT.
> 
> What is the resolution for Matt's concern that this is wrong for MTL?

There are two explanations, one easy and one less easy.

The easy one: without this patch i915 doesn't boot on MTL!(*)

The second explanation is that in MTL the media engine has it's
own set of misc irq's registers and those are on a different GT
(Daniele pointed this out).

I sent this patch not to bypass any review, but to restart the
discussion as this patch was just dropped.

Thanks,
Andi


(*)
[drm] *ERROR* GT1: GUC: CT: No response for request 0x550a (fence 7)
[drm] *ERROR* GT1: GUC: CT: Sending action 0x550a failed (-ETIMEDOUT) status=0X0
[drm] *ERROR* GT1: GUC: Failed to enable usage stats: -ETIMEDOUT
[drm] *ERROR* GT1: GuC initialization failed -ETIMEDOUT
[drm] *ERROR* GT1: Enabling uc failed (-5)
[drm] *ERROR* GT1: Failed to initialize GPU, declaring it wedged!