Openmoko Bug #2322: Sandisk 8GB MicroSDHC locks up under stress

[Openmoko Public Trac]

#2322: Sandisk 8GB MicroSDHC locks up under stress
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 Reporter:  skliarie  |          Owner:  openmoko-devel
     Type:  defect    |         Status:  new           
 Priority:  normal    |      Milestone:                
Component:  unknown   |        Version:  unspecified   
 Severity:  normal    |       Keywords:                
 Haspatch:  0         |      Blockedby:                
Estimated:            |    Patchreview:                
 Blocking:            |   Reproducible:                
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 I have an Sandisk 8GB MicroSDHC card that works ok for small write
 operations (a megabyte or less), but once I start to stress writing
 buffers (e.g. cat /dev/zero > file), the SDHC locks up hard and following
 error appears in dmesg:

 <6>[ 9479.220000] glamo-mci glamo-mci.0: Error after cmd: 0x4120
 <3>[ 9479.220000] mmcblk0: error -110 sending read/write command, response
 0x0, card status 0x400900

 The kernel is provided by the android-on-freerunner week-2009-44 (cat
 /proc/version):
 Linux version 2.6.29-rc3-mokodev (serdar@…) (gcc version 4.2.1) #1 PREEMPT
 Sat Oct 24 16:06:35 CEST 2009

 To fix that, I had to do the following:
 cd /sys/module/glamo_mci/parameters/
 echo 5000000 > sd_max_clk
 echo 3 > sd_drive

 After the change, the write speed is acceptable 2.800 MBytes/s. (using
 uSD-USB adapter the write speed is 18MB/s).

 Please fix the kernel to automatically downrate on such cards. (The
 previous value of the sd_max_clk was 16666666).

 Find attached dmesg of the kernel boot (grep glamo) with the SD card.

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Ticket URL: <https://docs.openmoko.org/trac/ticket/2322>
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