Re: DMA errors with BCM4312 - an update

[Chris Vine <chris@cvine.freeserve.co.uk>]

On Tue, 24 Nov 2009 13:06:43 -0600
Larry Finger <Larry.Finger@lwfinger.net> wrote:
> This E-mail is to summarize what I have learned to date.
> 
> The pm_qos change does nothing useful. It may have helped a little,
> but the side effects are far worse than the benefits.
> 
> Most systems work better with b43 when warm booted after Broadcom's
> wl driver was loaded. The conclusion is that wl is making some change
> in the setup that b43 is not.
> 
> (3) Based on the above, I have done MMIO and PCI-E configuration
> tracing for the two drivers and found some real differences. After
> seeing these, I did more RE work, and found some setup for the PCI-E
> core that was missed earlier. I am still working on the changes. What
> I have completed is found at
> 
> http://bcm-v4.sipsolutions.net/PCI-E#PCI-E_Setup
> 
> I doubt that most of these new routines will affect the problem
> interfaces as they apply only to PCI-E core revisions 7 and 8. My
> BCM4312 has rev 9. I do not know what versions are giving the
> trouble. With SSB_DEBUG enabled, it will be in a log line as follows:
> 
> ssb: Core 3 found: PCI-E (cc 0x820, rev 0x09, vendor 0x4243)
> 
> If you are seeing the DMA error, please supply the above info.
> 
> The "PCI-E Miscellaneous Configuration" routine that is not yet
> finished does run on my system and is the source of the tracing
> differences. If the problem cards has a revision newer than 9, I will
> probably need an MMIO trace for your device.

This is mine, the same revision as yours, but which demonstrates the
DMA errors:

ssb: Core 0 found: ChipCommon (cc 0x800, rev 0x16, vendor 0x4243)
ssb: Core 1 found: IEEE 802.11 (cc 0x812, rev 0x0F, vendor 0x4243)
ssb: Core 2 found: PCMCIA (cc 0x80D, rev 0x0A, vendor 0x4243)
ssb: Core 3 found: PCI-E (cc 0x820, rev 0x09, vendor 0x4243)
ssb: Found rev 1 PMU (capabilities 0x02A62F01)
ssb: SPROM revision 8 detected.
ssb: Sonics Silicon Backplane found on PCI device 0000:03:00.0

Chris