On Wednesday 06 June 2012 15:14:48 Subhash Jadavani wrote: > > On 06/04/2012 06:35 PM, Marc Dietrich 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@xxxxxxxxxxxxxxx/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 checked the power class specification and MMC core driver handing, I don't > see any issue with it. As you mentioned the PWR_CL_* fields are having > non-zero values which means SWITCH (CMD6) will be sent to change the > POWER_CLASS and from the logs you have attached, this switch command tries > to set the POWER_CLASS to 3 which is resulting in SWITCH_ERROR in card and > that's why it fails. > > If the PWR_CL_* fields are 0s (that's the case with SanDisk eMMC as you > mentioned), SWITCH(cmd6) is not sent to the card. > > I was trying to check analyze more from logs and the above EXT_CSD fields > for Toshiba card. > > EXT_CSD[203] => PWR_CL_26_360 => 0x33 > EXT_CSD[202] => PWR_CL_52_360 => 0x33 > EXT_CSD[201] => PWR_CL_26_195 => 0x77 > EXT_CSD[200] => PWR_CL_52_195 => 0x77 > > >> [ 3.842382] mmc1: clock 48000000Hz busmode 2 powermode 2 cs 0 Vdd 20 > > width 0 timing 1 > Logs shows that clock = 48MHz, bus_width = 8-Bit, SDR mode, VDD = High > voltage range. This would mean power class for this configuration will be in > higher nibble of PWR_CL_52_360 field (EXT_CSD[202]) which is 0x3. > > >> [ 3.842390] mmc1: starting CMD6 arg 03bb0301 flags 0000049d > > "arg" field from this logs show that we are trying to set the POWER_CLASS > (EXT_CSD[187]) field to value 0x3 which is resulting in switch error which > ideally shouldn't. > > Just for experiment, can we hack the value set to POWER_CLASS field to 0x7 > instead of 0x3? If this doesn't work, you may try other values (starting > from 1 till 15) to see setting any of the non-zero value succeeds or not. I tried 1 to 10 (as this is a 4.41 card) and none of them worked (including 7). > > > I hope this problem can be fixed or if it can't, I hope that commit > > > 3d93576e (mmc: core: skip card initialization if power class selection > > > fails) is reverted until the issues are sorted out. > > 3d93576e is really not the issue here. Reverting that patch is just a bad > workaround to the problem. We should actually try to find why exactly > setting the POWER_CLASS field is failing? sure, that would be the best solution... Marc -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
