linux-kernel - RE: [char-misc-next 3/4] mei: pxp: re-enable client on errors

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Date:   Tue, 14 Nov 2023 18:40:26 +0000
From:   "Winkler, Tomas" <tomas.winkler@...el.com>
To:     "Teres Alexis, Alan Previn" <alan.previn.teres.alexis@...el.com>,
        "ville.syrjala@...ux.intel.com" <ville.syrjala@...ux.intel.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:     "Usyskin, Alexander" <alexander.usyskin@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "Lubart, Vitaly" <vitaly.lubart@...el.com>
Subject: RE: [char-misc-next 3/4] mei: pxp: re-enable client on errors



> -----Original Message-----
> From: Teres Alexis, Alan Previn <alan.previn.teres.alexis@...el.com>
> Sent: Tuesday, November 14, 2023 5:32 PM
> To: ville.syrjala@...ux.intel.com; Winkler, Tomas <tomas.winkler@...el.com>
> Cc: gregkh@...uxfoundation.org; Usyskin, Alexander
> <alexander.usyskin@...el.com>; linux-kernel@...r.kernel.org; intel-
> gfx@...ts.freedesktop.org; Lubart, Vitaly <vitaly.lubart@...el.com>
> Subject: Re: [char-misc-next 3/4] mei: pxp: re-enable client on errors
> 
> On Tue, 2023-11-14 at 16:00 +0200, Ville Syrjälä wrote:
> > On Wed, Oct 11, 2023 at 02:01:56PM +0300, Tomas Winkler wrote:
> > > From: Alexander Usyskin <alexander.usyskin@...el.com>
> > >
> > > Disable and enable mei-pxp client on errors to clean the internal state.
> >
> > This broke i915 on my Alderlake-P laptop.

This fix was already posted, just missed the merging window
https://lkml.org/lkml/2023/10/31/636

Greg can you please take this fix into v6.7-rc2 run, or I can repost it with the correct subject.
Thanks
Tomas


> >
> 
> 
> Hi Alex, i just relooked at the series that got merged, and i noticed that in patch
> #3 of the series, you had changed mei_pxp_send_message to return bytes sent
> instead of zero on success. IIRC, we had agreed to not effect the behavior of
> this component interface (other than adding the timeout) - this was the
> intention of Patch #4 that i was pushing for in order to spec the interface
> (which continues to say zero on success). We should fix this to stay with the
> original behavior - where mei-pxp should NOT send partial packets and will
> only return zero in success case where success is sending of the complete
> packets - so we don't need to get back the "bytes sent"
> from mei_pxp_send_message. So i think this might be causing the problem.
> 
> 
> Side note  to Ville:, are you enabling PXP kernel config by default in all MESA
> contexts? I recall that MESA folks were running some CI testing with enable
> pxp contexts, but didn't realize this is being enabled by default in all contexts.
> Please be aware that enabling pxp-contexts would temporarily disabled
> runtime-pm during that contexts lifetime.
> Also pxp contexts will be forced to be irrecoverable if it ever hangs.
> The former is a hardware architecture requirement but doesn't do anything if
> you're enabling display (which I beleive also blocks in ADL). The latter was a
> requirement to comply with Vulkan.
> 
> ...alan
>