Interesting development regarding b43 DMA ERROR

Interesting development regarding b43 DMA ERROR

[Larry Finger]

Yesterday, I had to go back to kernel 2.6.34 for a test of code to avoid ssb
load freezeups on my HP Mini 110 Netbook, which has the SPROM at offset 0x0800,
not 0x1000. As I had been using b43 for this BCM4312 (14e4:4315) card in DMA
mode without any problems, I was quite surprised to see the dreaded DMA errors.
I had attributed the lack of errors with wireless testing to be due to the AMI,
not Phoenix, BIOS in this machine. When I switched to mainline ('git describe'
reports it as v2.6.35-3370-gcdd854b), again it works.

AFAIK, none of any fixes that were put into wt to try to solve this problem had
any affect, yet the device now works here.

Is anyone else that had/has the DMA problem running 2.6.35 + updates from the
linux-2.6.git tree? If so, does your BCM4312 now work with b43, or is my box
special?

Larry

Re: Interesting development regarding b43 DMA ERROR

[Rafał Miłecki]

2010/8/5 Larry Finger <Larry.Finger@lwfinger.net>:
> Yesterday, I had to go back to kernel 2.6.34 for a test of code to avoid ssb
> load freezeups on my HP Mini 110 Netbook, which has the SPROM at offset 0x0800,
> not 0x1000. As I had been using b43 for this BCM4312 (14e4:4315) card in DMA
> mode without any problems, I was quite surprised to see the dreaded DMA errors.
> I had attributed the lack of errors with wireless testing to be due to the AMI,
> not Phoenix, BIOS in this machine. When I switched to mainline ('git describe'
> reports it as v2.6.35-3370-gcdd854b), again it works.
>
> AFAIK, none of any fixes that were put into wt to try to solve this problem had
> any affect, yet the device now works here.
>
> Is anyone else that had/has the DMA problem running 2.6.35 + updates from the
> linux-2.6.git tree? If so, does your BCM4312 now work with b43, or is my box
> special?

Interesting. It means some patch that gone mainline fixed it and it
was submitted using other tree than w-t, right?

Would you care to bisect this?

-- 
Rafał

Re: Interesting development regarding b43 DMA ERROR

[Larry Finger]

On 08/06/2010 11:31 AM, Rafał Miłecki wrote:
> 
> Interesting. It means some patch that gone mainline fixed it and it
> was submitted using other tree than w-t, right?
> 
> Would you care to bisect this?

It won't be fun as this is a 1.6 GHz Atom and a kernel build is quite slow. In
addition, this one has the relocated SPROM that requires patching to be able to
boot. In the interests of the community, I will do it.

Larry

Re: Interesting development regarding b43 DMA ERROR

[Kalle Valo]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> On 08/06/2010 11:31 AM, Rafał Miłecki wrote:
>> 
>> Interesting. It means some patch that gone mainline fixed it and it
>> was submitted using other tree than w-t, right?
>> 
>> Would you care to bisect this?
>
> It won't be fun as this is a 1.6 GHz Atom and a kernel build is quite slow.

You can always build the kernel in another machine and just copy the
zImage and modules back to your netbook (or even create a monolithic
kernel without any modules). Also there are tools like distcc and
ccache which would help.

-- 
Kalle Valo