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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-06-12 16:53:38 +1000 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-06-12 16:53:38 +1000 |
commit | bc47ab0241c7c86da4f5e5f82fbca7d45387c18d (patch) | |
tree | b9c33ae8b6de43e44cc5fcbaa3e4a15f18a5ed42 /Documentation/DMA-API.txt | |
parent | 37f9ef553bed630957e025504cdcbc76f5de49d5 (diff) | |
parent | 8ebf975608aaebd7feb33d77f07ba21a6380e086 (diff) | |
download | blackbird-op-linux-bc47ab0241c7c86da4f5e5f82fbca7d45387c18d.tar.gz blackbird-op-linux-bc47ab0241c7c86da4f5e5f82fbca7d45387c18d.zip |
Merge commit 'origin/master' into next
Manual merge of:
arch/powerpc/kernel/asm-offsets.c
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 d9aa43d78bcc..25fb8bcf32a2 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 |