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* How to determinate max_req_size and max_blk_count settings
@ 2013-11-01  9:25 Axel Lin
  0 siblings, 0 replies; only message in thread
From: Axel Lin @ 2013-11-01  9:25 UTC (permalink / raw)
  To: linux-mmc; +Cc: Chris Ball

Hi,
I'm working on a sd/mmc driver.
The controller has a BLKLEN setting, however here is no register to set
block_count setting.
The datasheet says for Multi-Block Read/Write:
host needs to stop controller manually by setting STPCMD to 1 when all data is
received/transmitted. Host also needs to start CMD12 on the bus to stop the card.
The datasheet does not mention the limitation on block_count.

So my question is how to determinate max_req_size and max_blk_count settings in
driver since the controller only has a BLKLEN setting in register.

Yet another question is:
I got some messages while copying file to sd card:
[   35.602813] mmcblk0: error -5 transferring data, sector 11008, nr 64, cmd response 0x900, card status 0xc00
[   35.639143] end_request: I/O error, dev mmcblk0, sector 11008
[   35.645170] end_request: I/O error, dev mmcblk0, sector 11016
[   35.651690] end_request: I/O error, dev mmcblk0, sector 11024
[   35.658095] end_request: I/O error, dev mmcblk0, sector 11032
[   35.664090] end_request: I/O error, dev mmcblk0, sector 11040
[   35.670570] end_request: I/O error, dev mmcblk0, sector 11048
[   35.676541] end_request: I/O error, dev mmcblk0, sector 11056
[   35.682997] end_request: I/O error, dev mmcblk0, sector 11064

The copy looks success.
(Destination file size looks ok.
And if I copy an executable file, I can execute it.
So I think the copy is success.)

But I'm still have no idea how to debug such I/O error now.
Any comments/hits to debug such issue?

Thanks,
Axel



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