Libertas driver performance on Samsung platform

[Dan Williams]

On Sat, 2009-11-21 at 09:39 -0800, Ravi Mahadevappa wrote:
> Hi Dan, Jacky,
> 
> We are facing the same problem. Could you please elaborate a bit on
> this issue. 
> What is the firmware version and the driver version I should use? 

Latest driver from 2.6.31, which should also be pretty trivial to
backport to older kernels as well, since it doesn't change too much.
Either firmware v9 or firmware v8 can be used.  There is firmware
available here:

http://git.kernel.org/?p=linux/kernel/git/dwmw2/linux-firmware.git;a=tree;f=libertas;h=c9d61b10b750ccbfb8a6f26d8a762f4ca95df0e7;hb=HEAD

please use git to clone that repository to grab the firmware, since
trying to download the blob from gitweb over HTTP itself will likely
mess up the file.

> Where do I look to verify that the interrupt support is enabled?

In your SD host controller code.  You can also enable MMC/SD stack
debugging in your kernel config and get a lot more output about what's
going on.

Dan

> 
> Thanks,
> Ravi
> 
> On 11/15/2009 10:43 PM, Jacky Lam wrote: 
> > Dear Dan,
> > 
> > 	I just talk to tommy and find that the problem really happened in the
> > interrupt support as you said. Thanks for all advice from you.
> > 
> > BR,
> > Jacky
> > 
> > Dan Williams 提到:
> >   
> > > On Mon, 2009-11-16 at 09:43 +0800, Jacky Lam wrote:
> > >     
> > > > Dan Williams 提到:
> > > >       
> > > > > On Fri, 2009-11-13 at 13:12 +0800, Jacky Lam wrote:
> > > > >         
> > > > > > Dear all,
> > > > > > 
> > > > > > 	I have read the previous mail about the low performance of Samsung
> > > > > > BSP's SDIO platform driver when working with Libertas. I want to know if
> > > > > > anyone have tried the kernel mainstream's Samsung driver and have any
> > > > > > improvement on that?
> > > > > >           
> > > > > Does the Samsung SDHC have quirks or limitations with respect to DMA,
> > > > > block size, transfer width, etc?
> > > > > 
> > > > > Dan
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > >         
> > > > Dear Dan,
> > > > 
> > > > 	I look through the source code and can't find any "special" limitation
> > > > for the DMA, block size, transfer width.....Maybe I am not familiar
> > > > enough with Linux MMC stack. Could you tell me if there is any
> > > > requirement for the MMC stack on the host's DMA, block size, transfer
> > > > width..etc? So, I can pinpoint my investigation?
> > > >       
> > > There's no requirement in the stack, but the libertas driver and
> > > firmware expect multi-block transfer ability and interrupt support.  The
> > > libertas firmware will fail to load if if the host controller doesn't
> > > support multi-block, which we just found to be a limitation of one of
> > > the i.MX platform for example.
> > > 
> > > Dan
> > > 
> > > 
> > > 
> > > 
> > >     
> > 
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> >