Openmoko Bug #2217: Noise screen of death: Freerunner looses SDIO connection

[Openmoko Public Trac]

#2217: Noise screen of death: Freerunner looses SDIO connection
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 Reporter:  xbaldauf         |          Owner:  openmoko-kernel
     Type:  defect           |         Status:  new            
 Priority:  normal           |      Milestone:                 
Component:  System Software  |        Version:                 
 Severity:  major            |       Keywords:                 
 Haspatch:  0                |      Blockedby:                 
Estimated:                   |    Patchreview:                 
 Blocking:                   |   Reproducible:                 
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Comment(by xbaldauf):

 Replying to [comment:28 andy]:
 > I wonder if what has happened is that too much data is written from the
 SD Card unit in the Glamo (which is done by local Glamo DMA), so that it
 blows through the allocation of Glamo internal memory and wraps into an
 alias that is the framebuffer.

 Please also note that the noise does not always come. Often, the
 communication between CPU und SD card just fails, without exhibiting the
 screen corruption. For example, I've now tested kernel 2.6.24
 (http://git.openmoko.org/?p=kernel.git;a=commit;h=a1e97c611253511ffc2d8c45e3e6d6894fa03fa3
 , Sat, 23 Aug 2008 10:01:50 +0000 (11:01 +0100) ), and I now also
 experienced this bug:

 glamo-mci glamo-mci.0: Error after cmd: 0x8121
 glamo-mci glamo-mci.0: Error after cmd: 0x8123
 mmcblk0: error -84 sending read/write command
 end_request: I/O error, dev mmcblk0, sector 1992412
 glamo-mci glamo-mci.0: Error after cmd: 0x121
 glamo-mci glamo-mci.0: Error after cmd: 0x123
 mmcblk0: error -84 sending read/write command
 end_request: I/O error, dev mmcblk0, sector 1992412
 glamo-mci glamo-mci.0: Error after cmd: 0x8121
 glamo-mci glamo-mci.0: Error after cmd: 0x8123
 mmcblk0: error -84 sending read/write command
 end_request: I/O error, dev mmcblk0, sector 1992412
 glamo-mci glamo-mci.0: Error after cmd: 0x121
 glamo-mci glamo-mci.0: Error after cmd: 0x123
 mmcblk0: error -84 sending read/write command

 However, I did not see any screen corruption, I just could not tap button
 screen anymore (the application "qpe" did not react). I could kill "qpe"
 from the command line successfully, but the screen did change either
 (maybe the X server was affected, too). I could not access the filesystem
 anymore for new commands, but old commands like "dmesg" (I presume which
 were cached fully into RAM) still have been working.

 Having tested this under 2.6.24, the comment
 Replying to [comment:22 xbaldauf]:
 > I've never experienced this bug under kernel 2.6.24 AFAIK.
 is now wrong. :-(



 So maybe the screen corruption and the presumed DMA-wise overwrite is just
 a consequence of the communication problem between CPU and SD-card, and
 not the cause, but I do not know...

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2217#comment:30>
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