Messages in this thread Patch in this message | | | From | Joerg Roedel <> | Subject | [PATCH 4/4] dma-debug: add documentation for the driver filter | Date | Thu, 28 May 2009 17:19:31 +0200 |
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This patch adds the driver filter feature to the dma-debug documentation.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> --- Documentation/DMA-API.txt | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index d9aa43d..eb6f9d5 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -704,12 +704,23 @@ 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 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 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 -- 1.6.3.1
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