From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Greg KH <gregkh@linuxfoundation.org>,
balbi@ti.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
JBottomley@parallels.com, linux-scsi@vger.kernel.org,
davem@davemloft.net, netdev@vger.kernel.org,
Doug Thompson <dougthompson@xmission.com>,
linux-edac@vger.kernel.org, rjw@sisk.pl,
linux-pm@vger.kernel.org
Subject: Re: SYSFS "errors"
Date: Tue, 19 Feb 2013 07:03:10 -0300 [thread overview]
Message-ID: <20130219070310.2cadad7a@redhat.com> (raw)
In-Reply-To: <20130218224405.GB21493@pd.tnic>
Em Mon, 18 Feb 2013 23:44:05 +0100
Borislav Petkov <bp@alien8.de> escreveu:
> On Mon, Feb 18, 2013 at 02:26:18PM -0800, Greg KH wrote:
> > I don't know, it depends on if userspace can handle this properly or
> > not. What tools rely on this sysfs file? WHat happens when they get a
> > non-number in the file?
The thing with "sdram_scrub_rate" is that this is not supported by any
userspace application I know. I suspect that this is used by userspace
scripts. So, we'll never know in advance what behavior those scripts would
expect.
>
> I'm not aware of any, frankly speaking.
>
> If there are any, those tools should be able to handle the -ENODEV
> they get. Now, if this gets changed this way, the read would succeed
> but they'll have to parse the returned value and see that it is not an
> integer.
>
> So I don't know either.
>
> But my gut feeling says to stay concervative and not touch this code -
> we don't know what uses it and how much we would break by "fixing" it.
> The current situation is not that big of a deal IMVHO and I'd be willing
> to accept the small inconcistency versus possibly breaking userspace.
I remember I saw some discussions about it in the past at bluesmoke ML,
saying that -ENODEV is the expected behavior when this is not supported.
Changing from -ENODEV to "N/A" will break anything that would be relying
on the previous behavior. So, I think that such change will for sure break
userspace.
If we're willing to change it, not creating the "sdram_scrub_rate" sysfs
node is less likely to affect userspace.
Regards,
Mauro
next prev parent reply other threads:[~2013-02-19 10:03 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-18 15:33 SYSFS "errors" Felipe Balbi
2013-02-18 15:50 ` Greg KH
2013-02-18 15:52 ` Felipe Balbi
2013-02-18 17:13 ` Greg KH
2013-02-18 17:27 ` Felipe Balbi
2013-02-18 17:45 ` Borislav Petkov
2013-02-18 18:47 ` Felipe Balbi
2013-02-18 19:40 ` Borislav Petkov
2013-02-18 20:04 ` Felipe Balbi
2013-02-18 17:49 ` Greg KH
2013-02-18 18:46 ` Felipe Balbi
2013-02-18 19:46 ` Mauro Carvalho Chehab
2013-02-18 20:05 ` Felipe Balbi
2013-02-18 21:47 ` Mauro Carvalho Chehab
2013-02-18 21:54 ` Greg KH
2013-02-18 22:13 ` Borislav Petkov
2013-02-18 22:26 ` Greg KH
2013-02-18 22:44 ` Borislav Petkov
2013-02-19 10:03 ` Mauro Carvalho Chehab [this message]
2013-02-19 10:11 ` Felipe Balbi
2013-02-19 11:11 ` Mauro Carvalho Chehab
2013-02-19 11:43 ` Borislav Petkov
2013-02-19 12:16 ` Mauro Carvalho Chehab
2013-02-19 12:35 ` Borislav Petkov
2013-02-19 12:46 ` Mauro Carvalho Chehab
2013-02-19 13:06 ` Borislav Petkov
2013-02-19 13:15 ` Felipe Balbi
2013-02-19 13:28 ` Borislav Petkov
2013-02-19 13:38 ` Felipe Balbi
2013-02-19 13:50 ` Mauro Carvalho Chehab
2013-02-19 13:55 ` Borislav Petkov
2013-02-19 13:50 ` Borislav Petkov
2013-02-19 13:58 ` Hannes Reinecke
2013-02-19 14:10 ` Borislav Petkov
2013-02-19 14:14 ` Mauro Carvalho Chehab
2013-02-19 14:19 ` Felipe Balbi
2013-02-19 14:35 ` Mauro Carvalho Chehab
2013-02-19 14:50 ` Borislav Petkov
2013-02-19 14:53 ` Felipe Balbi
2013-02-19 13:42 ` Mauro Carvalho Chehab
2013-02-18 21:48 ` Alan Stern
2013-02-18 21:57 ` Felipe Balbi
2013-02-19 7:41 ` Alexander Stein
2013-02-19 10:12 ` Felipe Balbi
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