linux-kernel - Re: [PATCH v5 0/4] drm/dp: Rework LTTPR transparent mode handling and add support to msm driver

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] [day] [month] [year] [list]

Message-ID: <frsbcvxcvtp45mh45cld3rzbgl52gomzmzs73crv53pwbc4fns@sygnt6z2avht>
Date: Fri, 21 Feb 2025 21:58:56 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abel Vesa <abel.vesa@...aro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
	Karol Herbst <kherbst@...hat.com>, Lyude Paul <lyude@...hat.com>, 
	Danilo Krummrich <dakr@...hat.com>, Jani Nikula <jani.nikula@...ux.intel.com>, 
	Rodrigo Vivi <rodrigo.vivi@...el.com>, Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>, 
	Tvrtko Ursulin <tursulin@...ulin.net>, Rob Clark <robdclark@...il.com>, 
	Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, Bjorn Andersson <andersson@...nel.org>, 
	Konrad Dybcio <konradybcio@...nel.org>, Johan Hovold <johan@...nel.org>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, nouveau@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org, 
	intel-xe@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org, 
	Johan Hovold <johan+linaro@...nel.org>, Imre Deak <imre.deak@...el.com>
Subject: Re: [PATCH v5 0/4] drm/dp: Rework LTTPR transparent mode handling
 and add support to msm driver

On Mon, Feb 03, 2025 at 12:57:55PM +0200, Abel Vesa wrote:
> Looking at both i915 and nouveau DP drivers, both are setting the first
> LTTPR (if found) in transparent mode first and then in non-transparent
> mode, just like the DP v2.0 specification mentions in section 3.6.6.1.
> 
> Being part of the standard, setting the LTTPR in a specific operation mode
> can be easily moved in the generic framework. So do that by adding a new
> helper.
> 
> Then, the msm DP driver is lacking any kind of support for LTTPR handling,
> so add it by reading the LTTPR caps for figuring out the number of LTTPRs
> found on plug detect and then do exactly what the i915 and nouveau drivers
> do with respect to toggling through operating modes, just like the
> up-mentioned section from DP spec describes.
> 
> At some point, link training per sub-segment will probably be needed, but
> for now, toggling the operating modes seems to be enough at least for the
> X Elite-based platforms that this patchset has been tested on.
> 
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>

[...]
> 
> ---
> Abel Vesa (4):
>       drm/dp: Add helper to set LTTPRs in transparent mode
>       drm/nouveau/dp: Use the generic helper to control LTTPR transparent mode
>       drm/i915/dp: Use the generic helper to control LTTPR transparent mode

Lyude, Jani, what would be your preferred way of merging these patches?
Would you ack merging of those through drm-misc or would you prefer for
the first patch only to be landed to drm-misc, which you can then pull
into nouveau and i915 trees.

>       drm/msm/dp: Add support for LTTPR handling
> 
>  drivers/gpu/drm/display/drm_dp_helper.c            | 61 ++++++++++++++++++++++
>  .../gpu/drm/i915/display/intel_dp_link_training.c  | 24 ++-------
>  drivers/gpu/drm/msm/dp/dp_display.c                | 15 ++++++
>  drivers/gpu/drm/nouveau/nouveau_dp.c               | 17 +-----
>  include/drm/display/drm_dp_helper.h                |  2 +
>  5 files changed, 85 insertions(+), 34 deletions(-)
> ---
> base-commit: 00f3246adeeacbda0bd0b303604e46eb59c32e6e
> change-id: 20241031-drm-dp-msm-add-lttpr-transparent-mode-set-136cd5bfde07
> 
> Best regards,
> -- 
> Abel Vesa <abel.vesa@...aro.org>
> 

-- 
With best wishes
Dmitry