SDIO stability [was Re: SDIO Performance once again]

[Dan Williams]

On Tue, 2009-02-10 at 10:31 +0100, Sven Neumann wrote:
> Hi,
> 
> On Mon, 2009-02-09 at 10:59 -0500, Dan Williams wrote:
> 
> > You might try using the MMC debug options to see what's actually
> > happening at the SDIO level, and see if there are errors even below the
> > libertas code.  If the MMC/SDIO stack and the card are having problems
> > talking, obviously the libertas driver is going to have problems too.
> 
> OK, I've enabled CONFIG_MMC_DEBUG in my kernel build. But I don't quite
> know how to interpret the debug output. What I get is something along
> these lines:
> 
> mmc1: starting CMD53 arg 9a000007 flags 000001b5
> mmc1:     blksz 256 blocks 7 flags 00000100 tsac 1000 ms nsac 0
> PXAMCI: irq 00000004 stat 00002040
> PXAMCI: irq 00000001 stat 00003940
> mmc1: req done (CMD53): 0: 00002000 00000000 00000000 00000035
> mmc1:     1792 bytes transferred: 0
> PXAMCI: irq 00000800 stat 0000b940
> mmc1: starting CMD52 arg 00000a00 flags 00000195
> PXAMCI: irq 00000004 stat 0000a140
> mmc1: req done (CMD52): 0: 00001002 00000000 00000000 00000034
> mmc1: starting CMD52 arg 10000a00 flags 00000195
> PXAMCI: irq 00000004 stat 0000a140
> mmc1: req done (CMD52): 0: 00001002 00000000 00000000 00000034
> mmc1: starting CMD52 arg 90000afd flags 00000195
> PXAMCI: irq 00000004 stat 00002140
> mmc1: req done (CMD52): 0: 000010fd 00000000 00000000 00000034
> mmc1: starting CMD52 arg 10004000 flags 00000195
> PXAMCI: irq 00000004 stat 00002140
> mmc1: req done (CMD52): 0: 00001009 00000000 00000000 00000034
> 
> Sorry if that is a stupid question. But what should I be looking out for
> to determine if the MMC/SDIO stack and the card are having problems
> talking to each other?

You'd see error messages and MMC/SD host register dumps if stuff starts
going wrong.  If you don't see anything that looks suspicious, then it
may not be the host controller.

Dan