Hi Jai,
Thanks for debugging the issue.
On 25-Aug-23 16:32, Jai Luthra wrote:
> Fix the NULL pointer dereference when no monitor is connected, and the
> sound card is opened from userspace.
>
> Instead return an error as EDID information cannot be provided to
> the sound framework if there is no connector attached.
>
> Fixes: e0fd83dbe924 ("drm: bridge: it66121: Add audio support")
> Reported-by: Nishanth Menon <nm@xxxxxx>
> Closes: https://lore.kernel.org/all/20230825105849.crhon42qndxqif4i@gondola/
> Signed-off-by: Jai Luthra <j-luthra@xxxxxx>
> ---
> drivers/gpu/drm/bridge/ite-it66121.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
> index 466641c77fe9..d6fa00dea464 100644
> --- a/drivers/gpu/drm/bridge/ite-it66121.c
> +++ b/drivers/gpu/drm/bridge/ite-it66121.c
> @@ -1446,6 +1446,11 @@ static int it66121_audio_get_eld(struct device *dev, void *data,
> {
> struct it66121_ctx *ctx = dev_get_drvdata(dev);
>
> + if (!ctx->connector) {
> + dev_dbg(dev, "No connector present, cannot provide EDID data");
> + return -EINVAL;
> + }
> +
There are not many HDMI bridges that support codecs in the kernel, but
upon a quick look, bridge/analogix/anx7625.c and
bridge/synopsys/dw-hdmi* gracefully return a buffer of 0s when the
connector is unavailable.
I am not sure why that is done, but I also don't see the hdmi-codec
driver handle the 0s situation properly. It is business as usual for the
hdmi-codec.
Did you come across some observation when you were testing?
Regards
Aradhya
> mutex_lock(&ctx->lock);
>
> memcpy(buf, ctx->connector->eld,
>
> ---
> base-commit: 6269320850097903b30be8f07a5c61d9f7592393
> change-id: 20230825-it66121_edid-6ee98517808b
>
> Best regards,
