[PATCH v2] drm/ast: Fix ast_dp connection status

[Thomas Zimmermann]

Hi


Am 24.01.25 um 15:11 schrieb Jocelyn Falempe:
> ast_dp_is_connected() used to also check for link training success
> to report the DP connector as connected. Without this check, the
> physical_status is always connected. So if no monitor is present, it
> will fail to read the EDID and set the default resolution to 640x480
> instead of 1024x768.
>
> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
> Fixes: 2281475168d2 ("drm/ast: astdp: Perform link training during atomic_enable")
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Dave Airlie <airlied at redhat.com>
> Cc: dri-devel at lists.freedesktop.org
> Cc: <stable at vger.kernel.org> # v6.12+

I cannot reproduce the problem, but the patch looks correct. My AST2600 
with ASTDP still works correctly with the patch allied.

Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>

Best regards
Thomas

> ---
>   drivers/gpu/drm/ast/ast_dp.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/ast/ast_dp.c b/drivers/gpu/drm/ast/ast_dp.c
> index 0e282b7b167c..30aad5c0112a 100644
> --- a/drivers/gpu/drm/ast/ast_dp.c
> +++ b/drivers/gpu/drm/ast/ast_dp.c
> @@ -17,6 +17,12 @@ static bool ast_astdp_is_connected(struct ast_device *ast)
>   {
>   	if (!ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDF, AST_IO_VGACRDF_HPD))
>   		return false;
> +	/*
> +	 * HPD might be set even if no monitor is connected, so also check that
> +	 * the link training was successful.
> +	 */
> +	if (!ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDC, AST_IO_VGACRDC_LINK_SUCCESS))
> +		return false;
>   	return true;
>   }
>   
>
> base-commit: 798047e63ac970f105c49c22e6d44df901c486b2

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)