Re: [PATCH 1/2] drm/amd/display: Fix HPD consideration for VGA/LVDS connectors on DCE

[Mario Limonciello <superm1@kernel.org>]

On 8/21/26 16:50, Timur Kristóf wrote:
> After a refactor that landed in Linux 7.0,
> DC now crashes when it is initialized on GPUs
> that have a VGA or LVDS connector. This is because
> these connectors have no HPD so the hpd_gpio is NULL
> and therefore DC takes the code path meant for
> DCN 4.2+ which sets irq_source_hpd = 255 that
> causes the subsequent code to try to register
> the HPD interrupt, which fails, and causes
> a crash.
> 
> This commit should be backported to Linux 7.0 and newer.
Unfortunately 7.0.y is EoL.  But we'll get it in 7.1.y and later.

> 
> Cc: Dmytro Laktyushkin <dmytro.laktyushkin@amd.com>
> Cc: Roman Li <roman.li@amd.com>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5490
> Fixes: def3488eb0fd ("drm/amd/display: refactor HPD to increase flexibility")
> Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

I'll get this committed to amd-staging-drm-next.
> ---
>   drivers/gpu/drm/amd/display/dc/link/link_factory.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/link/link_factory.c b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
> index 8560ee727bfa..a83693ea43c0 100644
> --- a/drivers/gpu/drm/amd/display/dc/link/link_factory.c
> +++ b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
> @@ -643,7 +643,7 @@ static bool construct_phy(struct dc_link *link,
>   
>   		DC_LOG_DC("BIOS object table - hpd_gpio id: %d", enc_init_data.hpd_gpio->id);
>   		DC_LOG_DC("BIOS object table - hpd_gpio en: %d", enc_init_data.hpd_gpio->en);
> -	} else {
> +	} else if (link->ctx->dce_version > DCN_VERSION_4_01) {
>   		struct graphics_object_hpd_info hpd_info;
>   
>   		if (link->ctx->dc_bios->funcs->get_hpd_info(link->ctx->dc_bios, link->link_id, &hpd_info) == BP_RESULT_OK) {