3b6054da68
There is a race condition in the USB hub code with regard to handling TT clear requests that can get the HCD driver in a deadlock. Usually when an TT clear request is scheduled it will be executed immediately: <7>[ 6.077583] usb 2-1.3: unlink qh1-0e01/f4d4db00 start 0 [1/2 us] <3>[ 6.078041] usb 2-1: clear tt buffer port 3, a3 ep2 t04048d82 <7>[ 6.078299] hub_tt_work:731 <7>[ 9.309089] usb 2-1.5: link qh1-0e01/f4d506c0 start 0 [1/2 us] <7>[ 9.324526] ehci_hcd 0000:00:1d.0: reused qh f4d4db00 schedule <7>[ 9.324539] usb 2-1.3: link qh1-0e01/f4d4db00 start 0 [1/2 us] <7>[ 9.341530] usb 1-1.1: link qh4-0e01/f397aec0 start 2 [1/2 us] <7>[ 10.116159] usb 2-1.3: unlink qh1-0e01/f4d4db00 start 0 [1/2 us] <3>[ 10.116459] usb 2-1: clear tt buffer port 3, a3 ep2 t04048d82 <7>[ 10.116537] hub_tt_work:731 However, if a suspend operation is triggered before hub_tt_work is scheduled, hub_quiesce will cancel the work without notifying the HCD driver: <3>[ 35.033941] usb 2-1: clear tt buffer port 3, a3 ep2 t04048d80 <5>[ 35.034022] sd 0:0:0:0: [sda] Stopping disk <7>[ 35.034039] hub 2-1:1.0: hub_suspend <7>[ 35.034067] usb 2-1: unlink qh256-0001/f3b1ab00 start 1 [1/0 us] <7>[ 35.035085] hub 1-0:1.0: hub_suspend <7>[ 35.035102] usb usb1: bus suspend, wakeup 0 <7>[ 35.035106] ehci_hcd 0000:00:1a.0: suspend root hub <7>[ 35.035298] hub 2-0:1.0: hub_suspend <7>[ 35.035313] usb usb2: bus suspend, wakeup 0 <7>[ 35.035315] ehci_hcd 0000:00:1d.0: suspend root hub <6>[ 35.250017] PM: suspend of devices complete after 216.979 msecs <6>[ 35.250822] PM: late suspend of devices complete after 0.799 msecs <7>[ 35.252343] ehci_hcd 0000:00:1d.0: wakeup: 1 <7>[ 35.262923] ehci_hcd 0000:00:1d.0: --> PCI D3hot <7>[ 35.263302] ehci_hcd 0000:00:1a.0: wakeup: 1 <7>[ 35.273912] ehci_hcd 0000:00:1a.0: --> PCI D3hot <6>[ 35.274254] PM: noirq suspend of devices complete after 23.442 msecs <6>[ 35.274975] ACPI: Preparing to enter system sleep state S3 <6>[ 35.292666] PM: Saving platform NVS memory <7>[ 35.295030] Disabling non-boot CPUs ... <6>[ 35.297351] CPU 1 is now offline <6>[ 35.300345] CPU 2 is now offline <6>[ 35.303929] CPU 3 is now offline <7>[ 35.303931] lockdep: fixing up alternatives. <6>[ 35.304825] Extended CMOS year: 2000 When the device will resume the EHCI driver will get stuck in ehci_endpoint_disable waiting for the tt_clearing flag to reset: <0>[ 47.610967] usb 2-1.3: **** DPM device timeout **** <7>[ 47.610972] f2f11c60 00000092 f2f11c0c c10624a5 00000003 f4c6e880 c1c8a4c0 c1c8a4c0 <7>[ 47.610983] 15c55698 0000000b f56b34c0 f2a45b70 f4c6e880 00000082 f2a4602c f2f11c30 <7>[ 47.610993] c10787f8 f4cac000 f2a45b70 00000000 f4cac010 f2f11c58 00000046 00000001 <7>[ 47.611004] Call Trace: <7>[ 47.611006] [<c10624a5>] ? sched_clock_cpu+0xf5/0x160 <7>[ 47.611019] [<c10787f8>] ? lock_release_holdtime.part.22+0x88/0xf0 <7>[ 47.611026] [<c103ed46>] ? lock_timer_base.isra.35+0x26/0x50 <7>[ 47.611034] [<c17592d3>] ? schedule_timeout+0x133/0x290 <7>[ 47.611044] [<c175b43e>] schedule+0x1e/0x50 <7>[ 47.611051] [<c17592d8>] schedule_timeout+0x138/0x290 <7>[ 47.611057] [<c10624a5>] ? sched_clock_cpu+0xf5/0x160 <7>[ 47.611063] [<c103e560>] ? usleep_range+0x40/0x40 <7>[ 47.611070] [<c1759445>] schedule_timeout_uninterruptible+0x15/0x20 <7>[ 47.611077] [<c14935f4>] ehci_endpoint_disable+0x64/0x160 <7>[ 47.611084] [<c147d1ee>] ? usb_hcd_flush_endpoint+0x10e/0x1d0 <7>[ 47.611092] [<c1165663>] ? sysfs_add_file+0x13/0x20 <7>[ 47.611100] [<c147d5a9>] usb_hcd_disable_endpoint+0x29/0x40 <7>[ 47.611107] [<c147fafc>] usb_disable_endpoint+0x5c/0x80 <7>[ 47.611111] [<c147fb57>] usb_disable_interface+0x37/0x50 <7>[ 47.611116] [<c1477650>] usb_reset_and_verify_device+0x4b0/0x640 <7>[ 47.611122] [<c1474665>] ? hub_port_status+0xb5/0x100 <7>[ 47.611129] [<c147a975>] usb_port_resume+0xd5/0x220 <7>[ 47.611136] [<c148877f>] generic_resume+0xf/0x30 <7>[ 47.611142] [<c14821a3>] usb_resume+0x133/0x180 <7>[ 47.611147] [<c1473b10>] ? usb_dev_thaw+0x10/0x10 <7>[ 47.611152] [<c1473b1d>] usb_dev_resume+0xd/0x10 <7>[ 47.611157] [<c13baa60>] dpm_run_callback+0x40/0xb0 <7>[ 47.611164] [<c13bdb03>] ? pm_runtime_enable+0x43/0x70 <7>[ 47.611171] [<c13bafc6>] device_resume+0x1a6/0x2c0 <7>[ 47.611177] [<c13ba940>] ? dpm_show_time+0xe0/0xe0 <7>[ 47.611183] [<c13bb0f9>] async_resume+0x19/0x40 <7>[ 47.611189] [<c10580c4>] async_run_entry_fn+0x64/0x160 <7>[ 47.611196] [<c104a244>] ? process_one_work+0x104/0x480 <7>[ 47.611203] [<c104a24c>] ? process_one_work+0x10c/0x480 <7>[ 47.611209] [<c104a2c0>] process_one_work+0x180/0x480 <7>[ 47.611215] [<c104a244>] ? process_one_work+0x104/0x480 <7>[ 47.611220] [<c1058060>] ? async_schedule+0x10/0x10 <7>[ 47.611226] [<c104c15c>] worker_thread+0x11c/0x2f0 <7>[ 47.611233] [<c104c040>] ? manage_workers.isra.27+0x1f0/0x1f0 <7>[ 47.611239] [<c10507f8>] kthread+0x78/0x80 <7>[ 47.611244] [<c1750000>] ? timer_cpu_notify+0xd6/0x20d <7>[ 47.611253] [<c1050780>] ? __init_kthread_worker+0x60/0x60 <7>[ 47.611258] [<c176357e>] kernel_thread_helper+0x6/0xd <7>[ 47.611283] ------------[ cut here ]------------ This patch changes hub_quiesce behavior to flush the TT clear work instead of canceling it, to make sure that no TT clear request remains uncompleted before suspend. Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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|---|---|---|
| .. | ||
| atm | ||
| c67x00 | ||
| chipidea | ||
| class | ||
| core | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| phy | ||
| renesas_usbhs | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-common.c | ||
| usb-skeleton.c | ||
README
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.