DMA errors with BCM4312 - an update

DMA errors with BCM4312 - an update

[Larry Finger]

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.

Larry

Re: DMA errors with BCM4312 - an update

[Chris Vine]

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

Re: DMA errors with BCM4312 - an update

[Michael Buesch]

On Tuesday 24 November 2009 22:15:52 Chris Vine wrote:
> 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)

Larry, do you also have the same PMU?

-- 
Greetings, Michael.

Re: DMA errors with BCM4312 - an update

[Larry Finger]

On 11/24/2009 03:20 PM, Michael Buesch wrote:
> On Tuesday 24 November 2009 22:15:52 Chris Vine wrote:
>> 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)
> 
> Larry, do you also have the same PMU?

ssb: Found rev 1 PMU (capabilities 0x02A62F01)

Yes - seems to be identical.

Larry