linux-kernel - Re: [PATCH v2 2/5] drm: bridge: dw_hdmi: default enable workaround to clear the overflow

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: <50460cf7-34e9-7c8e-131b-6866f43ec2da@baylibre.com>
Date:   Fri, 8 Apr 2022 14:20:49 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Sandor Yu <Sandor.yu@....com>, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, andrzej.hajda@...el.com,
        robert.foss@...aro.org, Laurent.pinchart@...asonboard.com,
        jonas@...boo.se, jernej.skrabec@...il.com, hverkuil-cisco@...all.nl
Cc:     shengjiu.wang@....com, cai.huoqing@...ux.dev, maxime@...no.tech,
        harry.wentland@....com
Subject: Re: [PATCH v2 2/5] drm: bridge: dw_hdmi: default enable workaround to
 clear the overflow

On 08/04/2022 12:32, Sandor Yu wrote:
> i.MX8MPlus (v2.13a) has verified need the workaround to clear the
> overflow with one iteration.
> Only i.MX6Q(v1.30a) need the workaround with 4 iterations,
> the others versions later than v1.3a have been identified as needing
> the workaround with a single iteration.
> 
> Default enable the workaround with one iteration for all versions
> later than v1.30a.
> 
> Signed-off-by: Sandor Yu <Sandor.yu@....com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 23 +++++++----------------
>   1 file changed, 7 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 4befc104d220..02d8f7e08814 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2086,30 +2086,21 @@ static void dw_hdmi_clear_overflow(struct dw_hdmi *hdmi)
>   	 * then write one of the FC registers several times.
>   	 *
>   	 * The number of iterations matters and depends on the HDMI TX revision
> -	 * (and possibly on the platform). So far i.MX6Q (v1.30a), i.MX6DL
> -	 * (v1.31a) and multiple Allwinner SoCs (v1.32a) have been identified
> -	 * as needing the workaround, with 4 iterations for v1.30a and 1
> -	 * iteration for others.
> -	 * The Amlogic Meson GX SoCs (v2.01a) have been identified as needing
> -	 * the workaround with a single iteration.
> -	 * The Rockchip RK3288 SoC (v2.00a) and RK3328/RK3399 SoCs (v2.11a) have
> -	 * been identified as needing the workaround with a single iteration.
> +	 * (and possibly on the platform).
> +	 * 4 iterations for i.MX6Q(v1.30a) and 1 iteration for others.
> +	 * i.MX6DL (v1.31a), Allwinner SoCs (v1.32a), Rockchip RK3288 SoC (v2.00a),
> +	 * Amlogic Meson GX SoCs (v2.01a), RK3328/RK3399 SoCs (v2.11a)
> +	 * and i.MX8MPlus (v2.13a) have been identified as needing the workaround
> +	 * with a single iteration.
>   	 */
>   
>   	switch (hdmi->version) {
>   	case 0x130a:
>   		count = 4;
>   		break;
> -	case 0x131a:
> -	case 0x132a:
> -	case 0x200a:
> -	case 0x201a:
> -	case 0x211a:
> -	case 0x212a:
> +	default:
>   		count = 1;
>   		break;
> -	default:
> -		return;
>   	}
>   
>   	/* TMDS software reset */

Acked-by: Neil Armstrong <narmstrong@...libre.com>