Re: [PATCH] [drm][i915] Increase LSPCON timeout

From: Jani Nikula <jani.nikula@intel.com>
To: "Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Fredrik Schön" <fredrikschon@gmail.com>
Cc: intel-gfx@lists.freedesktop.org,
	"Fredrik Schön" <fredrik.schon@gmail.com>
Subject: Re: [PATCH] [drm][i915] Increase LSPCON timeout
Date: Thu, 16 Aug 2018 10:17:47 +0300	[thread overview]
Message-ID: <87tvnu7pb8.fsf@intel.com> (raw)
In-Reply-To: <20180815224540.GK4070@intel.com>

On Wed, 15 Aug 2018, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> On Wed, Aug 15, 2018 at 03:39:40PM -0700, Rodrigo Vivi wrote:
>> On Mon, Aug 13, 2018 at 07:51:33PM +0200, Fredrik Schön wrote:
>> 
>> First of all we need to fix the commit subject:
>> 
>> drm/i915: Increase LSPCON timeout
>> 
>> (this can be done when merging, no need to resend)
>> 
>> > 100 ms is not enough time for the LSPCON adapter on Intel NUC devices to
>> > settle. This causes dropped display modes at driver initialisation.
>> > 
>> > Increase timeout to 1000 ms.
>> > 
>> > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1570392
>> 
>> Missusage of "Fixes:" tag, please read
>> 
>> https://01.org/linuxgraphics/gfx-docs/maintainer-tools/drm-intel.html#fixes
>> 
>> But also no need for resending... could be fixed when merging
>> 
>> The right one would be:
>> 
>> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1570392
>> Fixes: 357c0ae9198a ("drm/i915/lspcon: Wait for expected LSPCON mode to settle")
>> Cc: Shashank Sharma <shashank.sharma@intel.com>
>> Cc: Imre Deak <imre.deak@intel.com>
>> Cc: Jani Nikula <jani.nikula@intel.com>
>> Cc: <stable@vger.kernel.org> # v4.11+
>> 
>> Since initial 100 seemed to be empirical and this increase seems to
>> help other cases I'm in favor of this move so
>> 
>> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> 
>> However I will wait a bit before merging it
>> so Imre, Shashank, and/or Jani can take a look here...
>
> now, really cc'ing them...

Shashank? Does this slow down non-LSPCON paths?

BR,
Jani.

>
>> 
>> > Signed-off-by: Fredrik Schön <fredrik.schon@gmail.com>
>> > ---
>> >  drivers/gpu/drm/i915/intel_lspcon.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> > 
>> > diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>> > index 8ae8f42f430a..be1b08f589a4 100644
>> > --- a/drivers/gpu/drm/i915/intel_lspcon.c
>> > +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>> > @@ -74,7 +74,7 @@ static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon,
>> >  	DRM_DEBUG_KMS("Waiting for LSPCON mode %s to settle\n",
>> >  		      lspcon_mode_name(mode));
>> >  
>> > -	wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 100);
>> > +	wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 1000);
>> >  	if (current_mode != mode)
>> >  		DRM_ERROR("LSPCON mode hasn't settled\n");
>> >  
>> > -- 
>> > 2.17.1
>> > 
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>> > Intel-gfx@lists.freedesktop.org
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-- 
Jani Nikula, Intel Open Source Graphics Center
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