Hi Manoj, On Mon, Jul 18 2011, Manoj Iyer wrote: > Right, without the patch I get.. > > [ 52.526665] mmc0: new SDHC card at address e624 > [ 52.571228] mmcblk0: mmc0:e624 SD16G 14.8 GiB > [ 52.591071] mmcblk0: retrying using single block read > [ 52.593105] mmcblk0: error -84 transferring data, sector 0, nr 8, > card status 0x900 > [ 52.593109] end_request: I/O error, dev mmcblk0, sector 0 > [ 52.594594] mmcblk0: error -84 transferring data, sector 1, nr 7, > card status 0x900 > [ 52.594604] end_request: I/O error, dev mmcblk0, sector 1 > [ 52.602893] quiet_error: 24 callbacks suppressed > [ 52.602902] Buffer I/O error on device mmcblk0, logical block 0 > [ 52.605349] ldm_validate_partition_table(): Disk read failed. > [ 52.605384] Dev mmcblk0: unable to read RDB block 0 > [ 52.607729] mmcblk0: unable to read partition table > u@u:~$ > > So, I cannot generate any comparison data with this SD card. I see, thanks. So we're lacking any data on what speed the card would normally provide. Perhaps you could try that card on a different controller, just so we're able to see whether it's usually possible to get closer to 45M/sec with it? I think I'll take your patch as-is for 3.1 -- since if there is a performance degradation, it's on cards that simply don't work at all right now -- and if you're able to work on a followup patch that only performs the clock-lowering after the first error, I think that'd be a handy patch to have around. Does that sound good? Thanks! - Chris. -- Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> One Laptop Per Child -- 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
