Re: powerbook/radeon PM problem

On Thu, 2007-02-01 at 20:11 +0100, Johannes Berg wrote:

Whenever I resume my powerbook I get:

[  336.307861] BUG: sleeping function called from invalid context at kernel/rwsem.c:20
[  336.307871] in_atomic():0, irqs_disabled():1
[  336.307875] Call Trace:
[  336.307879] [EC257D30] [C000901C] show_stack+0x3c/0x194 (unreliable)
[  336.307900] [EC257D60] [C00268B8] __might_sleep+0xd4/0xe8
[  336.307918] [EC257D70] [C004555C] down_read+0x24/0x5c
[  336.307930] [EC257D90] [C003A574] blocking_notifier_call_chain+0x20/0x54
[  336.307940] [EC257DB0] [C017FB60] fb_notifier_call_chain+0x24/0x34
[  336.307949] [EC257DC0] [C0180178] fb_set_suspend+0x58/0x6c
[  336.307956] [EC257DE0] [C01A79F0] radeonfb_pci_resume+0x1fc/0x3e0
[  336.307964] [EC257E00] [C01A7BF8] radeonfb_early_resume+0x24/0x40
[  336.307970] [EC257E20] [C001A5C0] pmac_call_early_video_resume+0x2c/0x3c
[  336.307985] [EC257E30] [C01E1148] pmu_ioctl+0x6f8/0xb64
[  336.307994] [EC257ED0] [C0091C84] do_ioctl+0x80/0x84
[  336.308003] [EC257EE0] [C0091D0C] vfs_ioctl+0x84/0x43c
[  336.308009] [EC257F10] [C0092104] sys_ioctl+0x40/0x74
[  336.308014] [EC257F40] [C00114B4] ret_from_syscall+0x0/0x38


Hence, there must be a bug somewhere... The documentation to
fb_set_suspend notes:
"It must be called with the console semaphore held"

Yeah well, it's -supposed- to be taken by the resume function, but the
early resume path is a hack that runs -really- early (so you get a
screen back for debugging). I should find a way to silence those stupid
warnings...

So that's one of the bugs, how can that be satisfied when we're just
resuming and haven't taken that semaphore? (if we did take it, then we'd
get the warning earlier..)

Then again, is the resume code really supposed to be called with
interrupts disabled?

Not normally... but when I wrote that stuff, there was no semaphore
involved in that code path... In fact, the semaphore we are taking
shouldn't be held by anybody else anyway..

I'm totally unsure what the correct fix for this is.

None other than removing the early wakeup hack :-(

Ben.