Re: 2.6.8 (or 7?) regression: sleep on older tibooks broken

[davidw@dedasys.com (David N. Welton)]

Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:

> > I made the video driver's sleep routing return 0 immediately.

> > That was enough to at least get a couple of reports from xmon
> > about a vector 200 corresponding to an address in
> > powerbook_sleep_Core99...  Still investigating, but this is new
> > territory for me, and it's certainly at a tricky moment in the
> > life of the kernel.  Suggestions appreciated as to what might have
> > changed and what to look for.

> Ouch, that's pretty bad. 200 is a machine check, looks like the HW
> shoked which shouldn't happen there. 

Ok, I'll try that.  Piddling around myself, I was tracing the crash to
on or around this code (via-pmu.c:2550):

	/* Save & disable L2 and L3 caches*/
//	save_l3cr = _get_L3CR();	/* (returns -1 if not available) */
//	save_l2cr = _get_L2CR();	/* (returns -1 if not available) */
/* 	if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
		_set_L3CR(save_l3cr & 0x7fffffff);  */
/* 	if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
		_set_L2CR(save_l2cr & 0x7fffffff);  */

commenting it out lets things go to sleep, although they don't seem to
wake up again.

> Can you get me the actual xmon output and eventually backtrace ?
> (you can disable the adb sleep code to get the kbd working in xmon)

that would be adb_notify_sleep?  ... yes, that seems to work ...

Managed to catch this:

Oops: machine check, sig: 7 [#1]
NIP: C025C5D8 LR: C025C768 SP: CD121E50 REGS: cd121da0 TRAP: 0200    Not tainted
MSR: 02043420 EE: 0 PR: 0 FP: 1 ME: 1 IR/DR: 10
TASK = cf4b0660[886] 'pmud' THREAD: cd120000Last syscall: 54 
GPR00: FFFFFFFF CD121E50 CF4B0660 39200000 00400000 00000000 FFFFFF10 02003032 
GPR08: 8014C0AC C025C768 00000004 00000000 88044428 1001E214 10010000 10000000 
GPR16: 10000000 10000000 10000000 7FFFFD48 10000000 00000001 46FFFFFF 00000000 
GPR24: FFFFFFFF 00000000 CD121E60 00000000 B9000000 20004200 FFFFFFE7 C0260000 
NIP [c025c5d8] 0xc025c5d8
LR [c025c768] 0xc025c768
Call trace:
 [c025cf34] 0xc025cf34
 [c006e0e0] sys_ioctl+0xdc/0x2f4
 [c0005f40] ret_from_syscall+0x0/0x44

So it's just getting the ioctcl and going into sleep_Core99.

The instructions around C025C5D8 look like:


c025c584:       48 00 9c 8d     bl      c0266210 <pmu_request>
c025c588:       7f 43 d3 78     mr      r3,r26
c025c58c:       48 00 9e 51     bl      c02663dc <pmu_wait_complete>
c025c590:       4b db 0e e1     bl      c000d470 <_get_L3CR>
c025c594:       7c 7b 1b 78     mr      r27,r3
c025c598:       7c 78 18 f8     not     r24,r3
c025c59c:       57 77 0f fe     rlwinm  r23,r27,1,31,31
c025c5a0:       4b db 0d d1     bl      c000d370 <_get_L2CR>
c025c5a4:       31 38 ff ff     addic   r9,r24,-1
c025c5a8:       7c 09 c1 10     subfe   r0,r9,r24
c025c5ac:       7c 7c 1b 78     mr      r28,r3
c025c5b0:       7c 09 b8 39     and.    r9,r0,r23
c025c5b4:       40 82 01 b8     bne-    c025c76c <powerbook_sleep_Core99+0x298>
c025c5b8:       7f 96 e0 f8     not     r22,r28
c025c5bc:       57 95 0f fe     rlwinm  r21,r28,1,31,31
c025c5c0:       31 36 ff ff     addic   r9,r22,-1
c025c5c4:       7c 09 b1 10     subfe   r0,r9,r22
c025c5c8:       7c 09 a8 39     and.    r9,r0,r21
c025c5cc:       40 82 01 94     bne-    c025c760 <powerbook_sleep_Core99+0x28c>
c025c5d0:       3f e0 c0 26     lis     r31,-16346
c025c5d4:       80 1f 78 c4     lwz     r0,30916(r31)
c025c5d8:       2c 00 00 00     cmpwi   r0,0
c025c5dc:       41 82 01 54     beq-    c025c730 <powerbook_sleep_Core99+0x25c>
c025c5e0:       3f 20 c0 27     lis     r25,-16345
c025c5e4:       4b ff f8 91     bl      c025be74 <save_via_state>
c025c5e8:       39 39 93 54     addi    r9,r25,-27820
c025c5ec:       80 09 00 94     lwz     r0,148(r9)
c025c5f0:       2c 00 00 00     cmpwi   r0,0
c025c5f4:       40 82 01 1c     bne-    c025c710 <powerbook_sleep_Core99+0x23c>
c025c5f8:       80 1f 78 c4     lwz     r0,30916(r31)
c025c5fc:       2c 00 00 00     cmpwi   r0,0
c025c600:       41 82 01 08     beq-    c025c708 <powerbook_sleep_Core99+0x234>
c025c604:       3f c0 01 21     lis     r30,289
c025c608:       3b e0 13 87     li      r31,4999
c025c60c:       3f a0 c0 23     lis     r29,-16349
c025c610:       63 de ea c0     ori     r30,r30,60096

I don't have too many ideas.  If it's useful, I suppose I can try
backing of to 2.6.7 to see if it suffers from the same problem...

Thankyou,
-- 
David N. Welton
     Personal: http://www.dedasys.com/davidw/
Free Software: http://www.dedasys.com/freesoftware/
   Apache Tcl: http://tcl.apache.org/
       Photos: http://www.dedasys.com/photos/