diff options
author | James Bottomley <James.Bottomley@HansenPartnership.com> | 2009-06-12 10:02:03 -0500 |
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committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2009-06-12 10:02:03 -0500 |
commit | 82681a318f9f028ea64e61f24bbd9ac535531921 (patch) | |
tree | 529b6a5b4fd040fb54b7672b1a224ebd47445876 /Documentation/DMA-API.txt | |
parent | 3860c97bd60a4525bb62eb90e3e7d2f02662ac59 (diff) | |
parent | 8ebf975608aaebd7feb33d77f07ba21a6380e086 (diff) |
[SCSI] Merge branch 'linus'
Conflicts:
drivers/message/fusion/mptsas.c
fixed up conflict between req->data_len accessors and mptsas driver updates.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'Documentation/DMA-API.txt')
-rw-r--r-- | Documentation/DMA-API.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index d9aa43d78bc..25fb8bcf32a 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -704,12 +704,24 @@ this directory the following files can currently be found: The current number of free dma_debug_entries in the allocator. + dma-api/driver-filter + You can write a name of a driver into this file + to limit the debug output to requests from that + particular driver. Write an empty string to + that file to disable the filter and see + all errors again. + If you have this code compiled into your kernel it will be enabled by default. If you want to boot without the bookkeeping anyway you can provide 'dma_debug=off' as a boot parameter. This will disable DMA-API debugging. Notice that you can not enable it again at runtime. You have to reboot to do so. +If you want to see debug messages only for a special device driver you can +specify the dma_debug_driver=<drivername> parameter. This will enable the +driver filter at boot time. The debug code will only print errors for that +driver afterwards. This filter can be disabled or changed later using debugfs. + When the code disables itself at runtime this is most likely because it ran out of dma_debug_entries. These entries are preallocated at boot. The number of preallocated entries is defined per architecture. If it is too low for you |