linux-kernel - Re: [PATCH v3] drm/msm/dpu: Add DSPP GC driver to provide GAMMA

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: <gmk7aho74xb2wwlc27t6qaozfnqsjjyccmzm5moe53tyzuwm4o@ri7cfoqz23ks>
Date: Tue, 28 Oct 2025 23:23:38 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: federico@...o.pro
Cc: Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        phone-devel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht,
        nicola@...na.info, David Heidelberg <david@...t.cz>,
        Guido Günther <agx@...xcpu.org>
Subject: Re: [PATCH v3] drm/msm/dpu: Add DSPP GC driver to provide GAMMA_LUT
 DRM property

On Sun, Oct 19, 2025 at 12:06:32PM +0200, Federico Amedeo Izzo via B4 Relay wrote:
> From: Federico Amedeo Izzo <federico@...o.pro>
> 
> Add support for DSPP GC block in DPU driver for Qualcomm SoCs.
> Expose the GAMMA_LUT DRM property, which is needed to enable
> night light and basic screen color calibration.
> 
> I used LineageOS downstream kernel as a reference and found the LUT
> format by trial-and-error on OnePlus 6.
> 
> Tested on oneplus-enchilada (sdm845-mainline 6.16-dev) and xiaomi-tissot
> (msm8953-mainline 6.12/main).
> 
> Tested-by: David Heidelberg <david@...t.cz>  # Pixel 3 (next-20251018)
> Tested-by: Guido Günther <agx@...xcpu.org> # on sdm845-shift-axolotl
> Signed-off-by: Federico Amedeo Izzo <federico@...o.pro>
> ---
> DRM GAMMA_LUT support was missing on sdm845 and other Qualcomm SoCs using
> DPU for CRTC. This is needed in userspace to enable features like Night
> Light or basic color calibration.
> 
> I wrote this driver to enable Night Light on OnePlus 6, and after the
> driver was working I found out it applies to the 29 different Qualcomm SoCs
> that use the DPU display engine, including X1E for laptops.
> 
> I used the LineageOS downstream kernel as reference and found the correct 
> LUT format by trial-and-error on OnePlus 6.
> 
> This was my first Linux driver and it's been a great learning
> experience.
> 
> The patch was reviewed by postmarketOS contributors here: 
> https://gitlab.com/sdm845-mainline/linux/-/merge_requests/137
> During review the patch was tested successfully on hamoa (X1E).
> ---
> Changes in v3:
> - Remove memset() after kzalloc() in dpu_crtc.c
> - Simplify error messages in dpu_crtc.c and dpu_hw_dspp.c
> - Use 0 for DPU_REG_WRITE() instead of reg = 0 in dpu_hw_dspp.c
> - Link to v2: https://lore.kernel.org/r/20251019-dpu-add-dspp-gc-driver-v2-1-30c8cb79cb17@izzo.pro
> 
> Changes in v2:
> - Fix gc register .len and .version in dpu_hw_catalog.c
> - Apply coding style suggestions
> - Link to v1: https://lore.kernel.org/r/20251018-dpu-add-dspp-gc-driver-v1-1-ed0369214252@izzo.pro
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c       | 86 +++++++++++++++++++++-----
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c |  4 ++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h |  4 ++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c     |  3 +
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c    | 54 ++++++++++++++++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.h    | 26 ++++++++
>  6 files changed, 163 insertions(+), 14 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>


-- 
With best wishes
Dmitry