> -----Original Message----- > From: Andrew Lunn <[email protected]> > Sent: Friday, February 20, 2026 10:19 AM > To: Shenwei Wang <[email protected]> > Cc: Arnaud POULIQUEN <[email protected]>; Linus Walleij > <[email protected]>; Bartosz Golaszewski <[email protected]>; Jonathan Corbet > <[email protected]>; Rob Herring <[email protected]>; Krzysztof Kozlowski > <[email protected]>; Conor Dooley <[email protected]>; Bjorn Andersson > <[email protected]>; Mathieu Poirier <[email protected]>; Frank Li > <[email protected]>; Sascha Hauer <[email protected]>; Shuah Khan > <[email protected]>; [email protected]; linux- > [email protected]; [email protected]; Pengutronix Kernel Team > <[email protected]>; Fabio Estevam <[email protected]>; Peng Fan > <[email protected]>; [email protected]; linux- > [email protected]; [email protected]; linux-arm- > [email protected]; dl-linux-imx <[email protected]>; Bartosz > Golaszewski <[email protected]> > Subject: [EXT] Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg GPIO driver > > Example: 32‑bit ARM vs 64‑bit ARM (AArch32 vs AArch64) Consider this > > message header: > > struct msg_hdr { > > u8 id; > > u32 size; > > u8 flags; > > }; > > That is just a bad design. The point of not allowing __packed is that it > forces you > to design your structures correctly. Maybe AI has no idea of taste, but > Maintainer > do and would not allow a u32 to be unaligned like this. >
Let’s keep the discussion technical instead of taste. 😊 My point with the earlier example was simply to illustrate how layout differences can happen across architectures or compilers. I’m more interested in understanding how you would prefer this specific structure to be defined so that it avoids unaligned fields while still maintaining a stable on‑wire format. For the rpmsg‑gpio driver specifically, I can drop the __packed annotation if that is the consensus, since the known configurations work without requiring it. Thanks, Shenwei > Andrew
