Re: [PATCH] usb: typec: ucsi: debugfs: Fix GET commands on UCSI < 2.0

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Sat, Oct 24, 2026 at 08:44:41PM +0300, Ali Ahmet Memiş wrote:
> Since the debugfs response buffer grew to 24 bytes, every GET command
> fails with -EINVAL on UCSI < 2.0, where the data length is limited to 16
> bytes. Clamp the length to UCSI_MAX_DATA_LENGTH().
> 
> Fixes: d9dc19910321 ("usb: typec: ucsi: Fix debugfs response truncation beyond 16 bytes")
> Signed-off-by: Ali Ahmet Memiş <aliamemis@disroot.org>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/ucsi/debugfs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/ucsi/debugfs.c b/drivers/usb/typec/ucsi/debugfs.c
> index 77a0dd75edd3..3cffd3778c67 100644
> --- a/drivers/usb/typec/ucsi/debugfs.c
> +++ b/drivers/usb/typec/ucsi/debugfs.c
> @@ -60,7 +60,8 @@ static int ucsi_cmd(void *data, u64 val)
>  	case UCSI_GET_LPM_PPM_INFO:
>  		ret = ucsi_send_command(ucsi, val,
>  					&ucsi->debugfs->response,
> -					sizeof(ucsi->debugfs->response));
> +					min(sizeof(ucsi->debugfs->response),
> +					    UCSI_MAX_DATA_LENGTH(ucsi)));
>  		break;
>  	default:
>  		ret = -EOPNOTSUPP;
> -- 
> 2.55.0

-- 
heikki