The SD card is read very slowly via the slot on the lap top, but faster via an external USB card reader, and other SD cards are read fine via the slot. So it must be a software issue? Something fuse or exfat related?
Here are the details:
I got a new video camera (Canon Vixia HFR800) and a SD card (SanDisk 128GB microSDxc V30 U3 A1).
I have lubuntu running on a Dell Inspiron 3521.
The camera formats the SD card to an exFAT filesystem. I installed exfat-fuse and exfat-utils, so that lubuntu could read the exFAT filesystem. That seemed to work fine.
Here's the problem: when I plug the sd card (micro sd with adapter) into the SD slot on the laptop and then try to copy files (typically 4GB each) from the SD card to the computer's internal hard drive, it is painfully slow (about 2mb/s). Other SD cards that I use for other devices work fine and transfer faster. Here's the strange part: when I take the weird slow card and put it back in the camera, and then use the camera's USB cable to transfer files (thus, using the camera as a card reader) then it transfers considerably faster at about 10mb/s.
Since other SD cards are read fine by my SD slot, it doesn't seem to be a computer hardware issue. Plus the camera, acting a USB card reader, reads the card faster than the computer's slot-- so it doesn't seem to be a SD card hardware issue either.
Thus it must be a software issue?
Could it have something to do with the fuse and exfat stuff? Somehow the read speed of this card in particular is being limited internally?
I've scoured the webs. Thanks all for your support..
Here is the output of dmesg after plugging in the sd card into the slot and then beginning to (slowly) copy a ~4gb file from the card to the hard drive:
[ 4479.856384] mmc0: new ultra high speed SDR50 SDXC card at address aaaa
[ 4479.856617] mmcblk0: mmc0:aaaa SP128 119 GiB
[ 4479.859572] mmcblk0: p1
[ 4512.326457] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4512.326460] mmcblk0: error -110 transferring data, sector 79104, nr 256, cmd response 0x900, card status 0x0
[ 4513.349774] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4513.349792] mmcblk0: error -110 transferring data, sector 79104, nr 256, cmd response 0x900, card status 0x0
[ 4513.349797] mmcblk0: retrying using single block read
[ 4514.214195] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4514.214199] mmcblk0: error -110 transferring data, sector 24183040, nr 256, cmd response 0x900, card status 0x0
[ 4515.430458] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4515.430461] mmcblk0: error -110 transferring data, sector 24188672, nr 256, cmd response 0x900, card status 0x0
[ 4516.422017] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4516.422021] mmcblk0: error -110 transferring data, sector 24188928, nr 256, cmd response 0x900, card status 0x0
[ 4517.478259] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4517.478262] mmcblk0: error -110 transferring data, sector 24190976, nr 256, cmd response 0x900, card status 0x0
[ 4518.534924] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4518.534927] mmcblk0: error -110 transferring data, sector 24192512, nr 256, cmd response 0x900, card status 0x0
[ 4519.558619] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4519.558623] mmcblk0: error -110 transferring data, sector 24192512, nr 256, cmd response 0x900, card status 0x0
[ 4519.558629] mmcblk0: retrying using single block read
[ 4520.422859] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4520.422862] mmcblk0: error -110 transferring data, sector 24194048, nr 256, cmd response 0x900, card status 0x0
and then it just kind continues on like that ad infinitum while copying the file very slowly
Actually, sometimes it goes fatal like this:
[ 4780.608716] mmcblk0: error -110 sending stop command, original cmd response 0x900, card status 0x900
[ 4780.608719] mmcblk0: error -110 transferring data, sector 24993024, nr 256, cmd response 0x900, card status 0x0
[ 4782.208596] mmcblk0: error -110 sending status command, retrying
[ 4782.816609] mmcblk0: error -110 sending status command, retrying
[ 4783.425014] mmcblk0: error -110 sending status command, aborting
[ 4785.856730] mmc0: card aaaa removed
[ 4785.856993] Buffer I/O error on dev mmcblk0p1, logical block 3120192, async page read
[ 4786.027462] Buffer I/O error on dev mmcblk0p1, logical block 4352, lost async page write
[ 4786.297551] mmc0: new ultra high speed SDR50 SDXC card at address aaaa
[ 4786.298042] mmcblk0: mmc0:aaaa SP128 119 GiB
[ 4786.301205] mmcblk0: p1
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