Re: power class selection fails on 3.5-rc1

[Marc Dietrich <marvin24@gmx.de>]

On Friday 08 June 2012 18:11:20 S, Venkatraman wrote:
> On Mon, Jun 4, 2012 at 10:05 PM, Marc Dietrich <marvin24@gmx.de> wrote:
> > Hi,
> > 
> > somehow I hope this would go away by itself, but it didn't :-( I reported
> > this problem some time ago (see: http://www.mail-archive.com/linux-
> > mmc@vger.kernel.org/msg13688.html ) but got no clear answer or fix.
> > 
> > In addition to the information I posted on the thread above, I also dumped
> > the contents of the ext_csd register file (where reg values are not
> > zero):
> > 
> > reg       Sandisk         Toshiba
> > 241     10      0x0a    50      0x32
> > 239     0       0x00    51      0x33
> > 238     0       0x00    119     0x77
> > 234     0       0x00    30      0x1e
> > 232     1       0x01    4       0x04
> > 231     21      0x15    21      0x15
> > 230     150     0x96    16      0x10
> > 229     150     0x96    66      0x42
> > 228     1       0x01    7       0x07
> > 226     8       0x08    16      0x10
> > 225     6       0x06    7       0x07
> > 224     4       0x04    8       0x08
> > 223     1       0x01    2       0x02
> > 222     8       0x08    16      0x10
> > 221     16      0x10    1       0x01
> > 220     8       0x08    7       0x07
> > 219     7       0x07    7       0x07
> > 217     16      0x10    17      0x11
> > 215     1       0x01    0       0x00
> > 214     218     0xda    238     0xee
> > 213     160     0xa0    128     0x80
> > 210     10      0x0a    0       0x00
> > 209     10      0x0a    60      0x3c
> > 208     10      0x0a    0       0x00
> > 207     10      0x0a    60      0x3c
> > 206     10      0x0a    0       0x00
> > 205     10      0x0a    30      0x1e
> > 203     0       0x00    51      0x33
> > 202     0       0x00    51      0x33
> > 201     0       0x00    119     0x77
> > 200     0       0x00    119     0x77
> > 196     3       0x03    7       0x07
> > 194     2       0x02    2       0x02
> > 192     5       0x05    5       0x05
> > 185     1       0x01    1       0x01
> > 181     0       0x00    1       0x01
> > 179     0       0x00    1       0x01
> > 175     0       0x00    1       0x01
> > 169     1       0x01    0       0x00
> > 168     0       0x00    2       0x02
> > 160     3       0x03    3       0x03
> > 158     0       0x00    3       0x03
> > 157     237     0xed    186     0xba
> > 
> > The second and the third column is from a device with a Sandisk eMCC which
> > works fine, while the last two columns are from a Toshiba eMMC which shows
> > the error. Looking into it, I found that only the Toshiba eMMC specifies
> > a powerclass in registers 203-200 while Sandisk does not, so the
> > powerclass is not changed in the latter case and the problem cannot be
> > triggered there.
> > 
> > I also attached a boot log with mmc debug enabled. I think there is not
> > much I can do else. Either this eMMC is just bogus and needs blacklisting
> > or there is some problem in the driver code.
> 
> I am a bit rusty here, so bear with me.
> According to the ext_csd, the power class value that should be sent to
> the card was 0x7. (Upper nibble of ext_csd[201]).

The card runs on 48 MHz, which means the 52 MHz value is choosen. The card is 
also a "dual-voltage" one (reg 196 = 7), which confuses me which value to 
select. But vdd reports 0x20 (3.2 - 3.3 V) so register 202 is the one to 
choose (contains 0x33) or "3" for a nibble.

But as I said before, neither 3 or 7 works.

Marc