Re: [PATCH AUTOSEL for 4.9 36/56] drm/i915: Fix the level 0 max_wm hack on VLV/CHV

[Jani Nikula]

On Fri, 17 Nov 2017, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Nov 17, 2017 at 01:28:05PM +0200, Jani Nikula wrote:
>> 
>> Cc: Greg
>> 
>> On Wed, 15 Nov 2017, Ville SyrjÃlà <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
>> > On Wed, Nov 15, 2017 at 04:44:54PM +0000, alexander.levin@xxxxxxxxxxx wrote:
>> >> On Wed, Nov 15, 2017 at 01:08:05PM +0200, Ville SyrjÃlà wrote:
>> >> >On Wed, Nov 15, 2017 at 02:45:43AM +0000, alexander.levin@xxxxxxxxxxx wrote:
>> >> >> From: Ville SyrjÃÂlÃÂ <ville.syrjala@xxxxxxxxxxxxxxx>
>> >> >>
>> >> >> [ Upstream commit 1be4d3793d5a93daddcd9be657c429b38ad750a3 ]
>> >> >>
>> >> >> The watermark should never exceed the FIFO size, so we need to
>> >> >> check against the current FIFO size instead of the theoretical
>> >> >> maximum when we clamp the level 0 watermark.
>> >> >>
>> >> >> Signed-off-by: Ville SyrjÃÂlÃÂ <ville.syrjala@xxxxxxxxxxxxxxx>
>> >> >> Link: https://urldefense.proofpoint.com/v2/url?u=http-3A__patchwork.freedesktop.org_patch_msgid_1480354637-2D14209-2D4-2Dgit-2Dsend-2Demail-2Dville.syrjala-40linux.intel.com&d=DwIDAw&c=udBTRvFvXC5Dhqg7UHpJlPps3mZ3LRxpb6__0PomBTQ&r=bUtaaC9mlBij4OjEG_D-KPul_335azYzfC4Rjgomobo&m=iuPtUar-VEGbH1jmVH_UTr4C02X8fmjHUfNYix-Yc0Y&s=ha_F0zP3A1Aztp5S5e6_bqdhiuuPXhn0dRWQ58vv3Is&e=
>> >> >> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
>> >> >> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
>> >> >
>> >> >Why are these patches being proposed for stable? They're not straight up
>> >> >fixes for known issues, and there's always a chance that something will
>> >> >break. Who is doing the qa on this?
>> >> 
>> >> Hi Ville,
>> >> 
>> >> They were selected automatically as part of a new process we're trying
>> >> out. If you disagree with the selection I'd be happy to drop it.
>> >
>> > How does that automatic process decide that a patch should be backported?
>> >
>> > drm and i915 are very fast moving targets so unintended side effects from
>> > backported patches is a real possibility. So I would recommend against
>> > backporting anything that isn't fixing a real issue affecting users. We
>> > do try to add the cc:stable to such patches.
>> 
>> Agreed.
>> 
>> First, I think an automatic backport process is against the stable
>> kernel rules (e.g. "It must fix a real bug that bothers people").
>
> It's finding lots of fixes that did bother people enough to submit a fix
> for.

I still have no idea how this autoselect picks up patches that do *not*
have cc: stable nor Fixes: from us. What information do you have that we
don't for making that call?

BR,
Jani.

>> Second, we can't and won't take any responsibility for backports we
>> didn't indicate with Cc: stable, a Fixes: tag, or a specific backport
>> request.
>
> Ok, you all are already totally messing with my normal stable workflow,
> so might as well just trust you all completely.  So let's just only take
> patches that you all do send me in the normal way.  It's easy for Sasha
> to filter out the drm/i915 patches from his results.
>
> Is that ok?
>
>> If you think there's a commit that should be backported and is known to
>> fix a user visible issue (as per the stable rules!), please check with
>> us first.
>
> Um, that is what he was doing with the cc: of you all on the patch
> itself that started this whole conversation...
>
> {sigh}
>
> greg k-h

-- 
Jani Nikula, Intel Open Source Technology Center