Re: [PATCH v2 1/2] mmc/host/rtsx: Configure SD_CFG2 register in sd_rw_multi

From: wwang
Date: Mon Nov 19 2012 - 21:42:27 EST


ä 2012å11æ20æ 10:21, Chris Ball åé:
Hi,

Sorry to be pedantic, but:

On Mon, Nov 19 2012, wei_wang@xxxxxxxxxxxxxx wrote:
For Realtek card reader, internal regsiter SD_CFG2 should be configured
before transferring data. In the prior version, the value of this register
has been calculated, but forgotten to write back to the internal register.
With what consequences? Was the data transfer failing? Under which
circumstances?

Thanks,

- Chris.

Hi Chris:

It's about compatibility issue. The default value of SD_CFG2 is proper for writing data. But for reading sequence, the timing is not good enough. So in some extreme circumstance, card reader may sample the response data from the card as good even if the data is wrong. And this will cause the bad consequence.

Shall I modify the commit and resend the patchset again?

BR,
Wei WANG
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/