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

[Jani Nikula]

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").

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.

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.


BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center