[U-Boot] Troubles accessing a USB mass storage device

["Ludovic Courtès" <ludo@gnu.org>]

ludo at gnu.org (Ludovic Court?s) writes:

> However, with a ?SD card in, with a valid MS-DOS partition table, it
> apparently fails to read from it:
>
> Marvell>> usb part
> ## Unknown partition table

Further investigation with all the debugging output enabled shows that
it?s the ?test unit ready? command (0x0) that fails:

--8<---------------cut here---------------start------------->8---
COMMAND phase
dir 0 lun 0 cmdlen 12 cmd 0065c1c4 datalen 0 pdata 0065c478
cmd[0] 0x0 cmd[1] 0x0 cmd[2] 0x0 cmd[3] 0x0 cmd[4] 0x0 cmd[5] 0x0 cmd[6] 0x0 cmd[7] 0x0 cmd[8] 0x0 cmd[9] 0x0 cmd[10] 0x0 cmd[11] 0x0 
STATUS phase
ptr[0] 0x55 ptr[1] 0x53 ptr[2] 0x42 ptr[3] 0x53 ptr[4] 0x7e ptr[5] 0x0 ptr[6] 0x0 ptr[7] 0x0 ptr[8] 0x0 ptr[9] 0x0 ptr[10] 0x0 ptr[11] 0x0 ptr[12] 0x1 
FAILED
COMMAND phase
dir 1 lun 0 cmdlen 12 cmd 0065c1c4 datalen 18 pdata 0065c1d4
cmd[0] 0x3 cmd[1] 0x0 cmd[2] 0x0 cmd[3] 0x0 cmd[4] 0x12 cmd[5] 0x0 cmd[6] 0x0 cmd[7] 0x0 cmd[8] 0x0 cmd[9] 0x0 cmd[10] 0x0 cmd[11] 0x0 
DATA phase
pdata[0] 0x70 pdata[1] 0x0 pdata[2] 0x2 pdata[3] 0x0 pdata[4] 0x0 pdata[5] 0x0 pdata[6] 0x0 pdata[7] 0xa pdata[8] 0x0 pdata[9] 0x0 pdata[10] 0x0 pdata[11] 0x0 pdata[12] 0x3a pdata[13] 0x0 pdata[14] 0x0 pdata[15] 0x0 pdata[16] 0x0 pdata[17] 0x0 
STATUS phase
ptr[0] 0x55 ptr[1] 0x53 ptr[2] 0x42 ptr[3] 0x53 ptr[4] 0x7f ptr[5] 0x0 ptr[6] 0x0 ptr[7] 0x0 ptr[8] 0x0 ptr[9] 0x0 ptr[10] 0x0 ptr[11] 0x0 ptr[12] 0x0 
Request Sense returned 02 3A 00
--8<---------------cut here---------------end--------------->8---

The request sense KCQ can be interpreted as ?Not Ready - Medium Not
Present?, according to
<https://secure.wikimedia.org/wikipedia/en/wiki/KCQ>, despite the fact
that the SD card is actually in (and Linux can successfully read from
it.)

The card reader has USB IDs 05e3:0726 (Genesys Logic).

Any idea how to go further?

Besides, ?usb_request_sense? and ?usb_test_unit_ready? both assume
LUN == 0.  Could it be a problem?

Thanks,
Ludo?.