-----Original Message-----
From: Andrew Lunn <andrew@lunn.ch>
Sent: Monday, October 13, 2025 11:56 AM
To: Shenwei Wang <shenwei.wang@nxp.com>
Cc: Bjorn Andersson <andersson@kernel.org>; Mathieu Poirier
[off-list ref]; Rob Herring [off-list ref]; Krzysztof
Kozlowski [off-list ref]; Conor Dooley [off-list ref]; Shawn
Guo [off-list ref]; Sascha Hauer [off-list ref]; Linus
Walleij [off-list ref]; Bartosz Golaszewski [off-list ref];
Pengutronix Kernel Team [off-list ref]; Fabio Estevam
[off-list ref]; Peng Fan [off-list ref]; linux-
remoteproc@vger.kernel.org; devicetree@vger.kernel.org; imx@lists.linux.dev;
linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; dl-linux-imx
[off-list ref]
Subject: [EXT] Re: [PATCH v3 3/4] gpio: imx-rpmsg: add imx-rpmsg GPIO driver

quoted

quoted

Notice how ENOPNOTSUPP can be 45, 122, 223, or 95. Returning
EL2NSYNC or EDQUOT to user space is going to cause confusion...

quoted

I think we should just follow the definitions in
include/uapi/asm-generic/errno.h, right?

No.

Try a make for mips, and look at includes you end up with. You will find it goes
something like:

# 1 "./arch/mips/include/asm/errno.h" 1
# 11 "./arch/mips/include/asm/errno.h"
# 1 "./arch/mips/include/uapi/asm/errno.h" 1 # 16
"./arch/mips/include/uapi/asm/errno.h"
# 1 "./include/uapi/asm-generic/errno-base.h" 1 # 17
"./arch/mips/include/uapi/asm/errno.h" 2

and this results in

#define EOPNOTSUPP      122     /* Operation not supported on transport
endpoint */

not what you get from asm-generic/errno.h:

#define EOPNOTSUPP      95      /* Operation not supported on transport endpoint
*/

That shouldn't be an issue in this case. 
For instance, if we define the error code as 1 in the return message, the driver will interpret it and just return -EOPNOTSUPP, regardless of the architecture.

Thanks,
Shenwei

        Andrew