[PATCH v3] drm: Print bad EDID notices less often

[Jani Nikula]

On Thu, 26 Sep 2024, Andi Kleen <ak at linux.intel.com> wrote:
> I have an old monitor that reports a zero EDID block, which results in a
> warning message. This happens on every screen save cycle, and maybe in
> some other situations, and over time the whole kernel log gets filled
> with these redundant messages.
>
> Make most of these prints conditional on bad_edid_count like other verbose EDID
> messages.

Honestly I think merging this would be counter-productive to addressing
the issue properly.

Please just give me the chance to look into it.

Is your zero EDID block the base block or an extension block?

BR,
Jani.


>
> Signed-off-by: Andi Kleen <ak at linux.intel.com>
>
> ---
>
> v2: Use bad_edid_count instead of _once.
> v3: Move rate limit logic into dedicated wrapper.
> ---
>  drivers/gpu/drm/drm_edid.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 855beafb76ff..64d41dd605f1 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1949,6 +1949,18 @@ static void edid_block_status_print(enum edid_block_status status,
>  	}
>  }
>  
> +static void edid_block_status_print_rl(struct drm_connector *connector,
> +				    enum edid_block_status status,
> +				    const struct edid *block,
> +				    int block_num)
> +{
> +	if (status != EDID_BLOCK_OK &&
> +		!connector->bad_edid_counter++ &&
> +		!drm_debug_enabled(DRM_UT_KMS))
> +		return;
> +	edid_block_status_print(status, block, block_num);
> +}
> +
>  static void edid_block_dump(const char *level, const void *block, int block_num)
>  {
>  	enum edid_block_status status;
> @@ -2375,7 +2387,7 @@ static struct edid *_drm_do_get_edid(struct drm_connector *connector,
>  
>  	status = edid_block_read(edid, 0, read_block, context);
>  
> -	edid_block_status_print(status, edid, 0);
> +	edid_block_status_print_rl(connector, status, edid, 0);
>  
>  	if (status == EDID_BLOCK_READ_FAIL)
>  		goto fail;
> @@ -2409,7 +2421,7 @@ static struct edid *_drm_do_get_edid(struct drm_connector *connector,
>  
>  		status = edid_block_read(block, i, read_block, context);
>  
> -		edid_block_status_print(status, block, i);
> +		edid_block_status_print_rl(connector, status, block, i);
>  
>  		if (!edid_block_status_valid(status, edid_block_tag(block))) {
>  			if (status == EDID_BLOCK_READ_FAIL)

-- 
Jani Nikula, Intel