Re: [PATCH] drm: Rename headers to match DP2.1 spec

[Thierry Reding <thierry.reding@gmail.com>]

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On Mon, Feb 06, 2023 at 02:37:08PM -0500, jdhillon wrote:
> This patch changes the headers defined in drm_dp.h to match
> the DP 2.1 spec.
> 
> Signed-off-by: Jasdeep Dhillon <jdhillon@amd.com>
> ---
>  drivers/gpu/drm/tegra/dp.c   |  2 +-
>  include/drm/display/drm_dp.h | 13 +++++++------
>  2 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c
> index 08fbd8f151a1..f33e468ece0a 100644
> --- a/drivers/gpu/drm/tegra/dp.c
> +++ b/drivers/gpu/drm/tegra/dp.c
> @@ -499,7 +499,7 @@ static int drm_dp_link_apply_training(struct drm_dp_link *link)
>  		for (i = 0; i < lanes; i++)
>  			values[i / 2] |= DP_LANE_POST_CURSOR(i, pc[i]);
>  
> -		err = drm_dp_dpcd_write(aux, DP_TRAINING_LANE0_1_SET2, values,
> +		err = drm_dp_dpcd_write(aux, DP_LINK_SQUARE_PATTERN, values,
>  					DIV_ROUND_UP(lanes, 2));
>  		if (err < 0) {
>  			DRM_ERROR("failed to set post-cursor: %d\n", err);
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index ed10e6b6f99d..2093c1f8d8e0 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -641,12 +641,11 @@
>  # define DP_LINK_QUAL_PATTERN_CUSTOM        0x40
>  # define DP_LINK_QUAL_PATTERN_SQUARE        0x48
>  
> -#define DP_TRAINING_LANE0_1_SET2	    0x10f
> -#define DP_TRAINING_LANE2_3_SET2	    0x110
> -# define DP_LANE02_POST_CURSOR2_SET_MASK    (3 << 0)
> -# define DP_LANE02_MAX_POST_CURSOR2_REACHED (1 << 2)
> -# define DP_LANE13_POST_CURSOR2_SET_MASK    (3 << 4)
> -# define DP_LANE13_MAX_POST_CURSOR2_REACHED (1 << 6)
> +#define DP_LINK_SQUARE_PATTERN				0x10f

I think it'd be better to add new definitions for these rather than
replace the existing ones. DP v1.2 calls these TRAINING_LANE0_1_SET2 and
TRAINING_LANE2_3_SET2, respectively, so within the context of DP v1.2
hardware the new names don't make any sense.

While at it, maybe add a comment to the new definitions that the old
ones were deprecated in DP v1.3 and have been repurposed in v2.0 and
v2.1, respectively.

Thierry

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