linux-kernel - Re: [PATCH v2 0/2] drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4133a684-61a1-4d18-bb25-212d5fdc5620@siemens.com>
Date: Mon, 26 Aug 2024 21:35:53 +0200
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Alexander Stein <alexander.stein@...tq-group.com>
Cc: Aradhya Bhatia <a-bhatia1@...com>, dri-devel@...ts.freedesktop.org,
 Marek Vasut <marex@...x.de>, Tomi Valkeinen
 <tomi.valkeinen@...asonboard.com>, Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Sam Ravnborg <sam@...nborg.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/2] drm/bridge: tc358767: Fix
 DRM_BRIDGE_ATTACH_NO_CONNECTOR case

On 24.06.24 12:17, Dmitry Baryshkov wrote:
> On Mon, 24 Jun 2024 at 13:07, Alexander Stein
> <alexander.stein@...tq-group.com> wrote:
>>
>> Hi,
>>
>> Am Montag, 24. Juni 2024, 11:49:04 CEST schrieb Dmitry Baryshkov:
>>> On Mon, Jun 24, 2024 at 03:07:10PM GMT, Aradhya Bhatia wrote:
>>>>
>>>>
>>>> On 22/06/24 17:49, Dmitry Baryshkov wrote:
>>>>> On Sat, Jun 22, 2024 at 05:16:58PM GMT, Aradhya Bhatia wrote:
>>>>>>
>>>>>>
>>>>>> On 17-Jun-24 13:41, Dmitry Baryshkov wrote:
>>>>>>> On Mon, Jun 17, 2024 at 07:40:32AM GMT, Jan Kiszka wrote:
>>>>>>>> On 16.02.24 15:57, Marek Vasut wrote:
>>>>>>>>> On 2/16/24 10:10, Tomi Valkeinen wrote:
>>>>>>>>>> Ok. Does anyone have a worry that these patches make the situation
>>>>>>>>>> worse for the DSI case than it was before? Afaics, if the DSI lanes
>>>>>>>>>> are not set up early enough by the DSI host, the driver would break
>>>>>>>>>> with and without these patches.
>>>>>>>>>>
>>>>>>>>>> These do fix the driver for DRM_BRIDGE_ATTACH_NO_CONNECTOR and DPI, so
>>>>>>>>>> I'd like to merge these unless these cause a regression with the DSI
>>>>>>>>>> case.
>>>>>>>>>
>>>>>>>>> 1/2 looks good to me, go ahead and apply .
>>>>>>
>>>>>> Isn't there any way for the second patch to move forward as well though?
>>>>>> The bridge device (under DPI to (e)DP mode) cannot really work without
>>>>>> it, and the patches have been pending idle for a long time. =)
>>>>>>
>>>>>>>>
>>>>>>>> My local patches still apply on top of 6.10-rc4, so I don't think this
>>>>>>>> ever happened. What's still holding up this long-pending fix (at least
>>>>>>>> for our devices)?
>>>>>>>
>>>>>>> Neither of the patches contains Fixes tags. If the first patch fixes an
>>>>>>> issue in previous kernels, please consider following the stable process.
>>>>>>>
>>>>>>> If we are unsure about the second patch, please send the first patch
>>>>>>> separately, adding proper tags.
>>>>>>>
>>>>>>
>>>>>> Thanks Dmitry! I can send the patches again with the required fixes
>>>>>> tags (or just patch-1 if we cannot do anything about patch-2).
>>>>>
>>>>> The problem with the second patch is that it get mixed reviews. I can
>>>>> ack the first patch, but for the second one I'd need a confirmation from
>>>>> somebody else. I'll go on and apply the first patch later today.
>>>>>
>>>>
>>>> Thanks Dmitry!
>>>>
>>>> However, would it be okay if I instead add another patch that makes 2
>>>> versions of the "tc_edp_bridge_funcs", say "tc_dpi_edp_bridge_funcs" and
>>>> "tc_dsi_edp_bridge_funcs", that have all the same function hooks except
>>>> for the .edid_read()?
>>>>
>>>> The dsi edid_read() will remain the same, and Tomi's patch - patch 2/2 -
>>>> will only fix the dpi version of the edid_read()?
>>>>
>>>> The bridge already has the capability to distinguish a DSI input from a
>>>> DPI input. This can be leveraged to decide which set of functions need
>>>> to be used without any major changes.
>>>
>>> I'd prefer if somebody with the DSI setup can ack / test the second
>>> patch.
>>>
>>>
>>
>> Now that my DSI-DP setup works apparently without issue I could test patch 2.
>> Since my setup does not use DRM_BRIDGE_ATTACH_NO_CONNECTOR (running on
>> drivers/gpu/drm/mxsfb/lcdif_drv.c), I can only say
>> there is no regression.
> 
> Let me send a (non-tested) patch, switching to drm_bridge_connector,
> then you can probably test both of them
> 

I suppose [1] was that follow-up, just not leading to success, right?

Now, what's next? I'd love to see the regression we have for the IOT2050 
devices finally fixed, even if it now only requires a short downstream
patch.

Jan

[1] https://lore.kernel.org/dri-devel/20240624-mxc-lcdif-bridge-attach-v1-1-37e8c5d5d934@linaro.org/

-- 
Siemens AG, Technology
Linux Expert Center