Greetings, I've been seeing mmc failures with Linux 4.10 on some IMX6 boards with UHS-I support when used with DDR50 cards (I've got a couple from different manufacturers). I do not see the same issues when using SDR104 cards. I can also see the issue on the latest linux-mmc repo. The issue is easily replicated by ejecting and inserting the DDR50 card A successful init looks like this: [ 150.514018] mmc0: host does not support reading read-only switch, assuming write-enable [ 150.578204] mmc0: new ultra high speed DDR50 SDHC card at address aaaa [ 150.592140] mmcblk0: mmc0:aaaa SL08G 7.40 GiB [ 150.611512] mmcblk0: p1 A failing init (about 1 of every 5 trys) looks like this: [ 49.514082] mmc0: host does not support reading read-only switch, assuming write-enable [ 49.676112] mmc0: tuning execution failed: -5 [ 49.680510] mmc0: ddr50 tuning failed [ 49.684206] mmc0: new ultra high speed DDR50 SDHC card at address aaaa [ 49.696456] mmcblk0: mmc0:aaaa SL08G 7.40 GiB ^^^^ failed to read the partition table and at this point all access fails: # dd if=/dev/mmcblk0 of=/dev/null bs=1k count=1 [ 89.417210] mmcblk0: error -84 transferring data, sector 0, nr 32, cmd response 0x900, card status 0xb00 1+0 records in 1+0 records out 1024 bytes (1.0 kB, 1.0 KiB) copied, 0.1227 s, 8.3 kB/s I know the issue started occurring in Linux v4.4 but I also have heard there are some tuning patches in the queue so before I bisected between v4.4 and v4.3. Note that v4.3 is missing DDR50 tuning but when I backport that I found that when ddr tuning failed there it did not cause the card to not be accessible. Regards, Tim -- 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
