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author | Ingo Molnar <mingo@elte.hu> | 2009-06-17 14:52:15 +0400 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-06-17 14:56:49 +0400 |
commit | eadb8a091b27a840de7450f84ecff5ef13476424 (patch) | |
tree | 58c3782d40def63baa8167f3d31e3048cb4c7660 /Documentation/DMA-API.txt | |
parent | 73874005cd8800440be4299bd095387fff4b90ac (diff) | |
parent | 65795efbd380a832ae508b04dba8f8e53f0b84d9 (diff) | |
download | linux-eadb8a091b27a840de7450f84ecff5ef13476424.tar.xz |
Merge branch 'linus' into tracing/hw-breakpoints
Conflicts:
arch/x86/Kconfig
arch/x86/kernel/traps.c
arch/x86/power/cpu.c
arch/x86/power/cpu_32.c
kernel/Makefile
Semantic conflict:
arch/x86/kernel/hw_breakpoint.c
Merge reason: Resolve the conflicts, move from put_cpu_no_sched() to
put_cpu() in arch/x86/kernel/hw_breakpoint.c.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/DMA-API.txt')
-rw-r--r-- | Documentation/DMA-API.txt | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index d9aa43d78bcc..5aceb88b3f8b 100644 --- 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 - 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 @@ -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 |