linux-kernel - snd_intel8x0m: error message because return value is unused?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <1298332643.11571.21.camel@t41.thuisdomein>
Date:	Tue, 22 Feb 2011 00:57:22 +0100
From:	Paul Bolle <pebolle@...cali.nl>
To:	linux-kernel@...r.kernel.org
Subject: snd_intel8x0m: error message because return value is unused?

0) In order to make a laptop run without error messages (ie, printks at
KERN_ERR level) I had to look at an error generated by snd_intel8x0m:

     ALSA intel8x0m.c:904: AC'97 warm reset still in progress? [0x2]

1) There's a datasheet one can study to understand that message. But
that seems not necessary here. It all boils down to the fact that this
test:

    if ((igetdword(chip, ICHREG(GLOB_CNT)) & ICH_AC97WARM) == 0)
            goto __ok;

will always fail so we'll never go to __ok and finally that error will
be printed. But if I simply change it into:

    cnt = igetdword(chip, ICHREG(GLOB_CNT));
    if ((cnt & ICH_AC97WARM) == 0)
            goto __ok;

this test will (always) succeed, we'll go to __ok and no error message
will be printed. So apparently, the error message was just a false
alarm.

2) Before I submit a (trivial) patch to fix this I'd like to better
understand what is going on here: is this standard C behavior, something
the build system asks the compiler to do, or maybe something else?

Paul Bolle

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/