linux-kernel - Re: [PATCH 1/3] drm/msm/dp: account for widebus in msm_dp_catalog_panel_tpg

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: <hwomnwmuak3optjooe6g5szqi77nc7znsfjrxqbxx72nqe3e7k@om2e65vaurov>
Date: Tue, 3 Dec 2024 16:34:08 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc: Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Stephen Boyd <swboyd@...omium.org>, 
	Kuogee Hsieh <quic_khsieh@...cinc.com>, linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	Jessica Zhang <quic_jesszhan@...cinc.com>
Subject: Re: [PATCH 1/3] drm/msm/dp: account for widebus in
 msm_dp_catalog_panel_tpg_enable()

On Mon, Dec 02, 2024 at 12:41:58PM -0800, Abhinav Kumar wrote:
> Adjust the h_active calculation to account for widebus in tpg.
> 
> Fixes: 757a2f36ab09 ("drm/msm/dp: enable widebus feature for display port")
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_catalog.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index b4c8856fb25d..05c8e1996f60 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -1011,9 +1011,21 @@ void msm_dp_catalog_panel_tpg_enable(struct msm_dp_catalog *msm_dp_catalog,
>  	u32 v_sync_width;
>  	u32 hsync_ctl;
>  	u32 display_hctl;
> +	u32 h_sync_width;
> +	u32 h_front_porch;
> +	u32 h_back_porch;
> +	u32 h_active;
> +
> +	h_active = drm_mode->hdisplay;
> +	h_back_porch = drm_mode->htotal - drm_mode->hsync_end;
> +	h_sync_width = drm_mode->htotal - (drm_mode->hsync_start + h_back_porch);

It's at least drm_mode->hsync_end - drm_mode->hsync_start

> +	h_front_porch = drm_mode->hsync_start - drm_mode->hdisplay;
> +
> +	if (msm_dp_catalog->wide_bus_en)
> +		h_active /= 2;
>  
>  	/* TPG config parameters*/
> -	hsync_period = drm_mode->htotal;
> +	hsync_period = h_sync_width + h_back_porch + h_active + h_front_porch;

Is it equivalent to:

hsync_period = drm_mode->htotal;
if (msm_dp_catalog->wide_bus_en)
    hsync_period -= drm_mode->hdisplay / 2;

I think it's simpler to handle.

>  	vsync_period = drm_mode->vtotal;
>  
>  	display_v_start = ((drm_mode->vtotal - drm_mode->vsync_start) *
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry