Hi,
On 08-09-15 17:38, Yousong Zhou wrote:
I just tried a method from allwinner's u-boot sources: retry the mode switch in
case of an error [1]. It was accompanied with a comment quoted below:
//retry for Toshiba emmc;for the first time Toshiba emmc change to HS
//it will return response crc err,so retry
Well, that 1GB card of mine is labeled as "pqi" made in Korea. This workaround
really worked and it succeeded on the second try, though I am not sure how
anti-spec this can be (the spec says a power reset SHOULD be done in the case
of crc error in the status data).
The above change alone can make the card work. I also noticed that allwinner's
uboot will disable the clock first before setting it and re-enable it
thereafter [2]. I can only guess that this is possibly some bugfix made
by engineers of allwinner. So I mimicked this approach and attached a patch
here.
Thanks for this. So if I understand you correctly then just the:
"mmc: retry in the case of failing to switch to HS mode"
Patch is enough to make things work, right ?
That makes sense because the clock dance you are subscribing is something which
allwinner does in many places and it really is not necessary.
Can you do a similar patch for the kernel and test that too ?
And once you've a working kernel patch submit that to Ulf, with the mmc
list in the Cc?
If Ulf is willing to take this fix on the kernel side (I'm the sunxi-mmc
maintainer
in the kernel, and the fix will get my ack), then I'm willing to take the u-boot
version of this fix.
Regards,
Hans
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