On Tue, Nov 12, 2013 at 01:33:11PM +0100, David Henningsson wrote: > Hi, > > This is a real oldie, but better late than never. > > A while back, I discovered that this patch would help against a kernel > panic when "cat /proc/asound/card0/codec0" was executed on this machine, > which was running an fglrx driver. > > I asked for a stable backport, but Takashi wanted testing to make sure > this was actually fixed by the patch [1]. And now, several months later, > I have this confirmation [2]. > > The test was conducted on an 3.5 Ubuntu kernel, based on the 3.5 > extended stable tree, but would apply equally well to 3.4. > > I'm attaching the backported patch - it applied cleanly, I've just added > an extra section with an explanation. >
Thank you David, I'll queue it for the 3.5 kernel. Cheers, -- Luis > -- David Henningsson, Canonical Ltd. https://launchpad.net/~diwic > > [1] > http://mailman.alsa-project.org/pipermail/alsa-devel/2013-March/060132.html > > [2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1212160/comments/4 > From 76aabf83ca9c8cff2dd9e3bb5300e3778e0baf7d Mon Sep 17 00:00:00 2001 > From: Takashi Iwai <ti...@suse.de> > Date: Wed, 20 Jun 2012 16:32:22 +0200 > Subject: [PATCH] ALSA: hda - Move one-time init codes from > generic_hdmi_init() > > The codes to initialize work struct or create a proc interface should > be called only once and never although it's called many times through > the init callback. Move that stuff into patch_generic_hdmi() so that > it's called only once. > > Signed-off-by: Takashi Iwai <ti...@suse.de> > > (cherry picked from commit 8b8d654b55648561287bd8baca0f75f964a17038) > > This is being backported to 3.4 and 3.5 due to prevention of kernel > panic. The kernel panic was observed by executing > 'cat /proc/asound/card0/codec0' on a particular machine, which was > - running in battery mode > - having an external HDMI monitor connected > - running the fglrx driver. > > In short, the one-time init code initializes a delayed_work struct. > Then, I believe the following happened: > 1) the delayed_work was activated > 2) the delayed_work struct was reinitialized by the init code > 3) when the delayed_work timed out (ready to run the callback function), > the kernel panic happened because the delayed_work struct had > been corrupted in step 2. > > BugLink: https://bugs.launchpad.net/bugs/1212160 > Signed-off-by: David Henningsson <david.hennings...@canonical.com> > --- > sound/pci/hda/patch_hdmi.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > > diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c > index 02a6e3f..ef917bf 100644 > --- a/sound/pci/hda/patch_hdmi.c > +++ b/sound/pci/hda/patch_hdmi.c > @@ -1282,23 +1282,34 @@ static int generic_hdmi_build_controls(struct > hda_codec *codec) > return 0; > } > > -static int generic_hdmi_init(struct hda_codec *codec) > +static int generic_hdmi_init_per_pins(struct hda_codec *codec) > { > struct hdmi_spec *spec = codec->spec; > int pin_idx; > > for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) { > struct hdmi_spec_per_pin *per_pin = &spec->pins[pin_idx]; > - hda_nid_t pin_nid = per_pin->pin_nid; > struct hdmi_eld *eld = &per_pin->sink_eld; > > - hdmi_init_pin(codec, pin_nid); > - snd_hda_jack_detect_enable(codec, pin_nid, pin_nid); > - > per_pin->codec = codec; > INIT_DELAYED_WORK(&per_pin->work, hdmi_repoll_eld); > snd_hda_eld_proc_new(codec, eld, pin_idx); > } > + return 0; > +} > + > +static int generic_hdmi_init(struct hda_codec *codec) > +{ > + struct hdmi_spec *spec = codec->spec; > + int pin_idx; > + > + for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) { > + struct hdmi_spec_per_pin *per_pin = &spec->pins[pin_idx]; > + hda_nid_t pin_nid = per_pin->pin_nid; > + > + hdmi_init_pin(codec, pin_nid); > + snd_hda_jack_detect_enable(codec, pin_nid, pin_nid); > + } > snd_hda_jack_report_sync(codec); > return 0; > } > @@ -1343,6 +1354,7 @@ static int patch_generic_hdmi(struct hda_codec *codec) > return -EINVAL; > } > codec->patch_ops = generic_hdmi_patch_ops; > + generic_hdmi_init_per_pins(codec); > > init_channel_allocations(); > > -- > 1.7.9.5 > -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1212160 Title: 'cat /proc/asound/card0/codec0' cause kernel panic (battery mode) To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1212160/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
