linux-kernel - Re: [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation

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: <ba56c822-cf3d-4d62-86d4-e04551e443c6@oss.qualcomm.com>
Date: Sat, 5 Oct 2024 18:31:09 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Jonathan Marek <jonathan@...ek.ca>, freedreno@...ts.freedesktop.org
Cc: Rob Clark <robdclark@...il.com>,
        Abhinav Kumar
 <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Jessica Zhang <quic_jesszhan@...cinc.com>,
        Konrad Dybcio <konradybcio@...nel.org>,
        "open list:DRM DRIVER for Qualcomm display hardware"
 <linux-arm-msm@...r.kernel.org>,
        "open list:DRM DRIVER for Qualcomm display hardware"
 <dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation

On 5.10.2024 4:38 PM, Jonathan Marek wrote:
> drm_mode_vrefresh() can introduce a large rounding error, avoid it.
> 
> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
> ---
>  drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 185d7de0bf376..1205aa398e445 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -542,7 +542,7 @@ static unsigned long dsi_adjust_pclk_for_compression(const struct drm_display_mo
>  
>  	int new_htotal = mode->htotal - mode->hdisplay + new_hdisplay;
>  
> -	return new_htotal * mode->vtotal * drm_mode_vrefresh(mode);
> +	return mult_frac(mode->clock * 1000u, new_htotal, mode->htotal);

This seems to ignore mult/div by two on certain mode flags.. is that
intended?

Konrad