Commit-ID: 016ea6874a6d58df85b54f56997d26df13c307b2 Gitweb: http://git.kernel.org/tip/016ea6874a6d58df85b54f56997d26df13c307b2 Author: Joerg Roedel <joerg.roedel@xxxxxxx> AuthorDate: Fri, 22 May 2009 21:57:23 +0200 Committer: Joerg Roedel <joerg.roedel@xxxxxxx> CommitDate: Tue, 2 Jun 2009 16:21:42 +0200 dma-debug: add documentation for the driver filter This patch adds the driver filter feature to the dma-debug documentation. Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx> --- 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 d9aa43d..25fb8bc 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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