Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

[pandora-kernel.git] / Documentation / DMA-API.txt

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index d9aa43d..5aceb88 100644 (file)
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -676,8 +676,8 @@ this directory the following files can currently be found:
        dma-api/all_errors      This file contains a numeric value. If this
                                value is not equal to zero the debugging code
                                will print a warning for every error it finds
        dma-api/all_errors      This file contains a numeric value. If this
                                value is not equal to zero the debugging code
                                will print a warning for every error it finds

-                               into the kernel log. Be carefull with this
-                               option. It can easily flood your logs.
+                               into the kernel log. Be careful with this
+                               option, as it can easily flood your logs.

 
        dma-api/disabled        This read-only file contains the character 'Y'
                                if the debugging code is disabled. This can
 
        dma-api/disabled        This read-only file contains the character 'Y'
                                if the debugging code is disabled. This can


@@ -704,12 +704,24 @@ this directory the following files can currently be found:
                                The current number of free dma_debug_entries
                                in the allocator.
 
                                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 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
 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