Re: [PATCH] ptp: ocp: Add newline to sysfs attribute output

[Zhongqiu Han]

On 11/3/2025 8:00 AM, Jakub Kicinski wrote:
> On Sat, 1 Nov 2025 23:45:00 +0000 Vadim Fedorenko wrote:
> > On 31/10/2025 23:59, Jakub Kicinski wrote:
> > > On Thu, 30 Oct 2025 20:45:19 +0800 Zhongqiu Han wrote:
> > > > Append a newline character to the sysfs_emit() output in ptp_ocp_tty_show.
> > > > This aligns with common kernel conventions and improves readability for
> > > > userspace tools that expect newline-terminated values.
> > >
> > > Vadim? Is the backward compat here a concern?
> >
> > Well, unfortunately, this patch breaks software we use:
> >
> > openat(AT_FDCWD, "/dev/ttyS4\n", O_RDWR|O_NONBLOCK) = -1 ENOENT (No such
> > file or directory)
> > newfstatat(AT_FDCWD, "/etc/localtime", {st_mode=S_IFREG|0644,
> > st_size=114, ...}, 0) = 0
> > write(2, "23:40:33 \33[31mERROR\33[0m ", 2423:40:33 ERROR ) = 24
> > write(2, "Could not open sa5x device\n", 27Could not open sa5x device
> >
> > So it looks like uAPI change, which is already used...
>
> Zhongqiu Han please consider sending a patch to add a comment above
> the unfortunate emit() explaining that we can't change it now.
> I get the feeling that otherwise this "fix" may resurface.

Hi Jakub,
Sure, will send the comment patch. Thanks


--
Thx and BRs,
Zhongqiu Han