On Tue, 8 Jun 2021, Maximilian Luz wrote:
> Getting a report (e.g. feature report) from a device requires us to send
> a request indicating which report we want to retrieve and then waiting
> for the corresponding response containing that report. We already
> provide the response structure to the request call, but the request
> isn't marked as a request that expects a response. Thus the request
> returns before we receive the response and the response buffer indicates
> a zero length response due to that.
>
> This essentially means that the get-report calls are broken and will
> always indicate that a report of length zero has been read.
>
> Fix this by appropriately marking the request.
>
> Fixes: b05ff1002a5c ("HID: Add support for Surface Aggregator Module HID transport")
> Signed-off-by: Maximilian Luz <luzmaximilian@xxxxxxxxx>
> ---
> drivers/hid/surface-hid/surface_hid.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hid/surface-hid/surface_hid.c b/drivers/hid/surface-hid/surface_hid.c
> index 3477b31611ae..a3a70e4f3f6c 100644
> --- a/drivers/hid/surface-hid/surface_hid.c
> +++ b/drivers/hid/surface-hid/surface_hid.c
> @@ -143,7 +143,7 @@ static int ssam_hid_get_raw_report(struct surface_hid_device *shid, u8 rprt_id,
> rqst.target_id = shid->uid.target;
> rqst.instance_id = shid->uid.instance;
> rqst.command_id = SURFACE_HID_CID_GET_FEATURE_REPORT;
> - rqst.flags = 0;
> + rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
> rqst.length = sizeof(rprt_id);
> rqst.payload = &rprt_id;
Queued in for-5.13/upstream-fixes branch, thanks.
--
Jiri Kosina
SUSE Labs
