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<20150213124125.67a67e04@recife.lan> Date: Fri, 13 Feb 2015 08:46:54 -0700 Message-ID: Subject: Re: DVB suspend/resume regression on 3.19 From: Shuah Khan To: Takashi Iwai Cc: Mauro Carvalho Chehab , Hans Verkuil , linux-media@vger.kernel.org, LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3920 Lines: 89 On Fri, Feb 13, 2015 at 8:34 AM, Shuah Khan wrote: > On Fri, Feb 13, 2015 at 8:12 AM, 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 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: >>> > > [] dump_trace+0x8c/0x340 >>> > > [] show_stack_log_lvl+0xa3/0x190 >>> > > [] show_stack+0x21/0x50 >>> > > [] dump_stack+0x47/0x67 >>> > > [] warn_slowpath_common+0x81/0xb0 >>> > > [] module_put+0xc7/0xd0 >>> > > [] dvb_usb_adapter_frontend_exit+0x41/0x60 [dvb_usb] >>> > > [] dvb_usb_exit+0x31/0xa0 [dvb_usb] >>> > > [] dvb_usb_device_exit+0x3b/0x50 [dvb_usb] >>> > > [] usb_unbind_interface+0x1ed/0x2c0 >>> > > [] __device_release_driver+0x7e/0x100 >>> > > [] device_release_driver+0x22/0x30 >>> > > [] usb_forced_unbind_intf+0x2d/0x60 >>> > > [] usb_suspend+0x73/0x130 >>> > > [] usb_dev_freeze+0x13/0x20 >>> > > [] dpm_run_callback+0x4a/0x150 >>> > > [] __device_suspend+0x121/0x350 >>> > > [] async_suspend+0x1e/0xa0 >>> > > [] async_run_entry_fn+0x43/0x150 >>> > > [] process_one_work+0x142/0x3f0 >>> > > [] worker_thread+0x114/0x460 >>> > > [] kthread+0xc1/0xe0 >>> > > [] 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. >>> > > > > Hi Takashi and Mauro, > > Looking at the stack trace usb_forced_unbind_intf() gets called from > usb_suspend(). Looks like the suspend path in unbind_no_pm_drivers_interfaces() > determines the driver doesn't have suspend/resume support and goes to > usb_forced_unbind_intf(). > > At this point forced unbinding results in release the driver via > usb_driver_release_interface(). > > It is worth looking into if the driver indeed has suspend/resume > routines? > I am not sure if firmware loading is the issue here. It becomes an issue in resume path if firmware isn't cached. I had to fix xc5000 driver to cache the firmware i.e don't release it after loading so it remains in the firmware cache for suspend/resume to find it. -- Shuah > >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-media" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/