Revision 43e58856585f8c61e6a4a0f1fd6996d78799a973 authored by Emmanuel Grumbach on 10 November 2011, 00:50:50 UTC, committed by John W. Linville on 11 November 2011, 16:03:24 UTC
When HW RF kill switch is set to kill the radio, our NIC issues an interrupt after we stop the APM module. When we unload the module, the driver disables and cleans the interrupts before stopping the APM. So we have a real interrupt (inta not zero) pending. When this interrupts pops up the tasklet has already been killed and we crash. Here is a logical description of the flow: disable and clean interrupts synchronize interrupts kill the tasklet stop the APM <<== creates an RF kill interrupt free_irq <<== somehow our ISR is called here and we crash Here is the panic message: [ 201.313636] BUG: unable to handle kernel paging request at ffff8800911b7150 [ 201.314541] IP: [<ffffffff8106d652>] tasklet_action+0x62/0x130 [ 201.315149] PGD 1c06063 PUD db37f067 PMD db408067 PTE 80000000911b7160 [ 201.316456] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [ 201.317324] CPU 1 [ 201.317495] Modules linked in: arc4 iwlwifi(-) mac80211 cfg80211 netconsole configfs binfmt_misc i915 drm_kms_helper drm uvcvideo i2c_algo_bit videodev dell_laptop dcdbas intel_agp dell_wmi intel_ips psmouse intel_gtt v4l2_compat_ioctl32 asix usbnet mii serio_raw video sparse_keymap firewire_ohci sdhci_pci sdhci firewire_core e1000e crc_itu_t [last unloaded: configfs] [ 201.323839] [ 201.324015] Pid: 2061, comm: modprobe Not tainted 3.1.0-rc9-wl #4 Dell Inc. Latitude E6410/0667CC [ 201.324736] RIP: 0010:[<ffffffff8106d652>] [<ffffffff8106d652>] tasklet_action+0x62/0x130 [ 201.325128] RSP: 0018:ffff88011bc43ea0 EFLAGS: 00010286 [ 201.325338] RAX: ffff88008ae70000 RBX: ffff8800911b7150 RCX: ffff88008ae70028 [ 201.325555] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88008ae70000 [ 201.325775] RBP: ffff88011bc43ec0 R08: 0000000000000000 R09: 0000000000000000 [ 201.325994] R10: 0000000000000002 R11: 0000000000000001 R12: 0000000000000001 [ 201.326212] R13: 0000000000000006 R14: 0000000000000100 R15: ffff88008e259fd8 [ 201.326431] FS: 00007f4b90ea9700(0000) GS:ffff88011bc40000(0000) knlGS:0000000000000000 [ 201.326657] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 201.326864] CR2: ffff8800911b7150 CR3: 000000008fd6d000 CR4: 00000000000006e0 [ 201.327083] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 201.327302] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 201.327521] Process modprobe (pid: 2061, threadinfo ffff88008e258000, task ffff88008ae70000) [ 201.327747] Stack: [ 201.330494] 0000000000000046 0000000000000030 0000000000000001 0000000000000006 [ 201.333870] ffff88011bc43f30 ffffffff8106cd8a ffffffff811e1016 ffff88011bc43f08 [ 201.337186] 0000000100000046 ffff88008e259fd8 0000000a10be2160 0000000000000006 [ 201.340458] Call Trace: [ 201.342994] <IRQ> [ 201.345656] [<ffffffff8106cd8a>] __do_softirq+0xca/0x250 [ 201.348185] [<ffffffff811e1016>] ? pde_put+0x76/0x90 [ 201.350730] [<ffffffff8131aeae>] ? do_raw_spin_unlock+0x5e/0xb0 [ 201.353261] [<ffffffff811e1016>] ? pde_put+0x76/0x90 [ 201.355776] [<ffffffff8163ccfc>] call_softirq+0x1c/0x30 [ 201.358287] [<ffffffff8101531d>] do_softirq+0x9d/0xd0 [ 201.360823] [<ffffffff8106cb05>] irq_exit+0xd5/0xf0 [ 201.363330] [<ffffffff8163d5d6>] do_IRQ+0x66/0xe0 [ 201.365819] [<ffffffff81632673>] common_interrupt+0x73/0x73 [ 201.368257] <EOI> Cc: <stable@kernel.org> 3.1+ Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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braille-console.txt
Linux Braille Console
To get early boot messages on a braille device (before userspace screen
readers can start), you first need to compile the support for the usual serial
console (see serial-console.txt), and for braille device (in Device Drivers -
Accessibility).
Then you need to specify a console=brl, option on the kernel command line, the
format is:
console=brl,serial_options...
where serial_options... are the same as described in serial-console.txt
So for instance you can use console=brl,ttyS0 if the braille device is connected
to the first serial port, and console=brl,ttyS0,115200 to override the baud rate
to 115200, etc.
By default, the braille device will just show the last kernel message (console
mode). To review previous messages, press the Insert key to switch to the VT
review mode. In review mode, the arrow keys permit to browse in the VT content,
page up/down keys go at the top/bottom of the screen, and the home key goes back
to the cursor, hence providing very basic screen reviewing facility.
Sound feedback can be obtained by adding the braille_console.sound=1 kernel
parameter.
For simplicity, only one braille console can be enabled, other uses of
console=brl,... will be discarded. Also note that it does not interfere with
the console selection mechanism described in serial-console.txt
For now, only the VisioBraille device is supported.
Samuel Thibault <samuel.thibault@ens-lyon.org>
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