Re: [PATCH] staging: greybus: hid: fix SET_REPORT return value

[Dan Carpenter]

On Fri, Jul 10, 2026 at 02:06:44AM +0800, Hao-Qun Huang wrote:
> On Jul 9, 2026 at 6:52 PM, Dan Carpenter <error27@xxxxxxxxx> wrote:
> > These kinds of changes require testing.  How have you tested this
> > change?
> 
> I compile-tested it (W=1, building gb-hid, greybus and hid together) and
> traced the return path by hand.  I don't have Greybus HID hardware and
> couldn't find a working emulator (gbsim has been dead since Ara), so I
> haven't run it on a live device.
> 
> The bug is that gb_hid_set_report() returns -errno on failure and len on
> success, and __gb_hid_output_raw_report() computes that into ret (even
> adding one back for the report ID byte) and then returns 0, discarding
> it.  So a successful hidraw write reports 0 bytes written and a failed
> SET_REPORT looks like success.  The GET path next to it already returns
> the count, as do usbhid, i2c-hid and uhid, so callers already handle a
> positive return and greybus HID was the only one returning 0.

The bug is not hard to understand, the issue is that this changes the
function completely...  Was nothing checking the return before?

regards,
dan carpenter