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<20150213124125.67a67e04@recife.lan> Date: Fri, 13 Feb 2015 08:34:15 -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: 3497 Lines: 79 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? -- 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/