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

[Dmitry Baryshkov]

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 at linaro.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 at linaro.org>
> 

-- 
With best wishes
Dmitry