At Fri, 13 Feb 2015 16:12:40 +0100, Takashi Iwai wrote: > > At Fri, 13 Feb 2015 12:41:25 -0200, > Mauro Carvalho Chehab wrote: > > > > Em Fri, 13 Feb 2015 15:02:42 +0100 > > Takashi Iwai <tiwai@xxxxxxx> escreveu: > > > > > At Mon, 09 Feb 2015 11:59:07 +0100, > > > Takashi Iwai wrote: > > > > > > > > Hi, > > > > > > > > we've got a bug report about the suspend/resume regression of DVB > > > > device with 3.19. The symptom is VLC doesn't work after S3 or S4 > > > > resume. strace shows that /dev/dvb/adaptor0/dvr returns -ENODEV. > > > > > > > > The reporter confirmed that 3.18 works fine, so the regression must be > > > > in 3.19. > > > > > > > > There is a relevant kernel warning while suspending: > > > > > > > > WARNING: CPU: 1 PID: 3603 at ../kernel/module.c:1001 module_put+0xc7/0xd0() > > > > Workqueue: events_unbound async_run_entry_fn > > > > 0000000000000000 ffffffff81a45779 ffffffff81664f12 0000000000000000 > > > > ffffffff81062381 0000000000000000 ffffffffa051eea0 ffff8800ca369278 > > > > ffffffffa051a068 ffff8800c0a18090 ffffffff810dfb47 0000000000000000 > > > > Call Trace: > > > > [<ffffffff810055ac>] dump_trace+0x8c/0x340 > > > > [<ffffffff81005903>] show_stack_log_lvl+0xa3/0x190 > > > > [<ffffffff81007061>] show_stack+0x21/0x50 > > > > [<ffffffff81664f12>] dump_stack+0x47/0x67 > > > > [<ffffffff81062381>] warn_slowpath_common+0x81/0xb0 > > > > [<ffffffff810dfb47>] module_put+0xc7/0xd0 > > > > [<ffffffffa04d98d1>] dvb_usb_adapter_frontend_exit+0x41/0x60 [dvb_usb] > > > > [<ffffffffa04d8451>] dvb_usb_exit+0x31/0xa0 [dvb_usb] > > > > [<ffffffffa04d84fb>] dvb_usb_device_exit+0x3b/0x50 [dvb_usb] > > > > [<ffffffff814cefad>] usb_unbind_interface+0x1ed/0x2c0 > > > > [<ffffffff8145ceae>] __device_release_driver+0x7e/0x100 > > > > [<ffffffff8145cf52>] device_release_driver+0x22/0x30 > > > > [<ffffffff814cf13d>] usb_forced_unbind_intf+0x2d/0x60 > > > > [<ffffffff814cf3c3>] usb_suspend+0x73/0x130 > > > > [<ffffffff814bd453>] usb_dev_freeze+0x13/0x20 > > > > [<ffffffff81468fca>] dpm_run_callback+0x4a/0x150 > > > > [<ffffffff81469c81>] __device_suspend+0x121/0x350 > > > > [<ffffffff81469ece>] async_suspend+0x1e/0xa0 > > > > [<ffffffff81081e63>] async_run_entry_fn+0x43/0x150 > > > > [<ffffffff81079e72>] process_one_work+0x142/0x3f0 > > > > [<ffffffff8107a234>] worker_thread+0x114/0x460 > > > > [<ffffffff8107f3b1>] kthread+0xc1/0xe0 > > > > [<ffffffff8166b77c>] ret_from_fork+0x7c/0xb0 > > > > > > > > So something went wrong in module refcount, which likely leads to > > > > disabling the device and returning -ENODEV in the end. > > > > > > > > Does this ring a bell to you guys? > > > > > > > > The hardware details and logs are found in the URL below: > > > > https://bugzilla.novell.com/show_bug.cgi?id=916577 > > > > > > I wonder whether no one hits the same problem...? > > > > Hi Takashi, > > > > There were no recent changes at dvb-usb core or at the dtt200u.c driver. > > So, I don't think that the regression was caused by a change at the media > > subsystem. Yet, we've added some patches to fix suspend/resume at the > > DVB core, but they basically add a new set of optional callbacks. So, it > > should not cause any regression. > > > > The changeset in question is 59d7889ae49f6e3e9d9cff8c0de7ad95d9ca068b. > > Hm, is this commit really merged between 3.18 and 3.19? > > > From those messages: > > > > 2015-02-06T15:30:47.468258+01:00 linux-z24t kernel: [ 150.552119] dvb-usb: downloading firmware from file 'dvb-usb-wt220u-fc03.fw' > > 2015-02-06T15:30:47.468827+01:00 linux-z24t mtp-probe: checking bus 1, device 5: "/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-4" > > 2015-02-06T15:30:47.879878+01:00 linux-z24t mtp-probe: bus: 1, device: 5 was not an MTP device > > 2015-02-06T15:30:47.880192+01:00 linux-z24t kernel: [ 151.992993] usb 1-4: USB disconnect, device number 5 > > 2015-02-06T15:30:47.880839+01:00 linux-z24t kernel: [ 151.993076] dvb-usb: generic DVB-USB module successfully deinitialized and disconnected. > > > > I _suspect_ that dvb_usb_download_firmware() failed to load the firmware > > file. > > > > That problem actually looks like a recently discovered issue:t > > request_firmware() fails during resume on some systems. What > > seems to happen in this case is that the media drivers are resumed > > _before_ mounting the partition where the firmware file is hosted. > > > > Yet, in this case, it should be printing: > > "did not find the firmware file." > > Right. This makes me wonder, too. > > > I would add a test patch in order to print the return code from > > dvb_usb_download_firmware(), in order to see if it succeeds or > > not, e. g. something like the patch below, and then try to narrow > > down where it is failing, assuming that the new message will be printed. > > > > If nothing gets printed, then I would try to discover why the USB > > stack disconnected the device. Perhaps an ehci/xhci bug? > > OK, I'll give a test kernel to report. The patched kernel didn't show the message. So it's not about the firmware load failure, apparently. Any other point to check? Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
