[mipsel+rs780e]Occasionally "GPU lockup" after resuming from suspend.

[Chen Jie]

Hi,

For this occasional GPU lockup when returns from STR/STD, I find
followings(when the problem happens):

The value of SRBM_STATUS is whether 0x20002040 or 0x20003040.
Which means:
* HI_RQ_PENDING(There is a HI/BIF request pending in the SRBM)
* MCDW_BUSY(Memory Controller Block is Busy)
* BIF_BUSY(Bus Interface is Busy)
* MCDX_BUSY(Memory Controller Block is Busy) if is 0x20003040
Are MCDW_BUSY and MCDX_BUSY two memory channels? What is the
relationship among GART mapped memory, On-board video memory and MCDX,
MCDW?

CP_STAT: the CSF_RING_BUSY is always set.

There are many CP_PACKET2(0x80000000) in CP ring(more than three hundreds). e.g.
r[131800]=0x00028000
r[131801]=0xc0016800
r[131802]=0x00000140
r[131803]=0x000079c5
r[131804]=0x0000304a
r[131805] ... r[132143]=0x80000000
r[132144]=0xffff0000
After the first reset, GPU will lockup again, this time, typically
there are 320 dwords in CP ring -- with 319 CP_PACKET2 and 0xc0033d00
in the end.
Are these normal?

BTW, is there any way for X to switch to NOACCEL mode when the problem
happens? Thus users will have a chance to save their documents and
then reboot machine.


Regards,
-- Chen Jie