At Fri, 12 Oct 2012 23:08:14 +0800, Daniel J Blueman wrote: > > On 10 October 2012 20:34, Takashi Iwai <ti...@suse.de> wrote: > > At Tue, 9 Oct 2012 22:26:40 +0800, > > Daniel J Blueman wrote: > >> On 9 October 2012 21:04, Takashi Iwai <ti...@suse.de> wrote: > >> > At Tue, 9 Oct 2012 19:23:56 +0800, > >> > Daniel J Blueman wrote: > >> >> On 9 October 2012 18:07, Takashi Iwai <ti...@suse.de> wrote: > >> >> > At Tue, 09 Oct 2012 12:04:08 +0200, > >> >> > Takashi Iwai wrote: > >> >> >> At Tue, 9 Oct 2012 00:34:09 +0800, > >> >> >> Daniel J Blueman wrote: > >> >> >> > On 8 October 2012 20:58, Takashi Iwai <ti...@suse.de> wrote: > >> >> >> > > At Tue, 25 Sep 2012 13:20:05 +0800, > >> >> >> > > Daniel J Blueman wrote: > >> >> >> > >> On my Macbook with a discrete Nvidia GPU, there is a race > >> >> >> > >> between > >> >> >> > >> selecting the integrated GPU and putting the discrete GPU into > >> >> >> > >> D3 [1], > >> >> >> > >> reliably causing a kernel oops [2]. > >> >> >> > >> > >> >> >> > >> Introducing a delay of ~1s between the calls prevents this. > >> >> >> > >> When the > >> >> >> > >> second 'OFF' write path executes, it looks like struct azx at > >> >> >> > >> card->private_data hasn't yet been allocated yet [3], so there > >> >> >> > >> is > >> >> >> > >> likely some locking missing. > >> >> >> > > > >> >> >> > > It's rather pci_get_drvdata() returning NULL (i.e. card is NULL, > >> >> >> > > thus > >> >> >> > > card->private_data causes Oops). Could you check the patch like > >> >> >> > > below > >> >> >> > > and see whether you get a kernel warning (but no Oops) or the > >> >> >> > > problem > >> >> >> > > gets fixed by shifting the assignment of pci drvdata? > >> >> >> > [...] > >> >> >> > > >> >> >> > Good patching. Calling pci_set_drvdata later prevents the oops in > >> >> >> > HDA, > >> >> >> > though we see unexpected 0x0 responses in the response ring buffer > >> >> >> > [1], which we don't see when there's a >~1.5s delay between IGD and > >> >> >> > OFF. > >> >> >> > >> >> >> If the previous patch fixed, it means that the switching occurred > >> >> >> during the device was being probed. Maybe a better approach to > >> >> >> register the VGA switcheroo after the proper initialization. > >> >> >> > >> >> >> The patch below is a revised one. Please give it a try. > >> >> > > >> >> > Also, it's not clear which card spews the spurious response. > >> >> > Apply the patch below in addition. > >> >> [...] > >> >> > >> >> hda-intel: 0000:01:00.1: spurious response 0x0:0x0, last cmd=0x1f0004 > >> >> $ lspci -s :1:0.1 > >> >> 01:00.1 Audio device: NVIDIA Corporation Device 0e1b (rev ff) > >> >> > >> >> It's the NVIDIA device which presumably hasn't completed it's > >> >> transition to D3 at the time the OFF is executed. > >> > > >> > OK, then could you try the patch below on the top of previous two > >> > patches? > >> > >> The first IGD switcheroo command fails to switch to the integrated GPU: > >> > >> # cat /sys/kernel/debug/vgaswitcheroo/switch > >> 0:DIS:+:Pwr:0000:01:00.0 > >> 1:IGD: :Pwr:0000:00:02.0 > >> 2:DIS-Audio: :Pwr:0000:01:00.1 > >> # echo IGD >/sys/kernel/debug/vgaswitcheroo/switch > >> vga_switcheroo: client 1 refused switch > >> > >> I also instrumented snd_hda_lock_devices, but none of the failure > >> paths are being taken, which would leave inconsistent state, as the > >> return value isn't checked. > > > > Hm, right, the return value of snd_hda_lock_devices() isn't checked, > > but I don't understand how this results like above. > > Basically switching is protected by mutex in vga_switcheroo.c, so the > > whole operation in the client side should be serialized. > > > > In anyway, try the patch below cleanly, and see the spurious message > > error coming up at which timing. > [...] > > The patch _does_ address the issue. A recent update to my Macbook > firmware misleadingly broke i915 switching, but since I can reproduce > the oops without the IGD switching completing with the stock kernel, > and consistently can't without [1], the patch is good. > > Tested-by: Daniel J Blueman <dan...@quora.org>
OK, then I'm going to apply the patch to 3.7 tree (with Cc to stable). thanks, Takashi > > Thanks Takashi! > Daniel > > --- [1] > > snd_hda_intel 0000:00:1b.0: enabling device (0000 -> 0002) > snd_hda_intel 0000:00:1b.0: irq 54 for MSI/MSI-X > XXX 0000:00:1b.0: azx_codec_create entered > vga_switcheroo: enabled > XXX 0000:00:1b.0: azx_codec_create done > input: HDA Intel PCH Headphone as > /devices/pci0000:00/0000:00:1b.0/sound/card0/input9 > snd_hda_intel 0000:01:00.1: enabling device (0000 -> 0002) > hda_intel: Disabling MSI > hda-intel: 0000:01:00.1: Handle VGA-switcheroo audio client > XXX 0000:01:00.1: azx_codec_create entered > XXX 0000:01:00.1: azx_codec_create done > input: HDA NVidia HDMI/DP,pcm=8 as > /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input12 > input: HDA NVidia HDMI/DP,pcm=7 as > /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input13 > input: HDA NVidia HDMI/DP,pcm=3 as > /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input14 > vga_switcheroo: client 1 refused switch > i915: switched off > -- > Daniel J Blueman > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
