Bug 2398
| Summary: | RFE: ACPI debug enhancements | ||
|---|---|---|---|
| Product: | ACPI | Reporter: | Len Brown (lenb) |
| Component: | Other | Assignee: | Zhu Yi (yi.zhu) |
| Status: | CLOSED CODE_FIX | ||
| Severity: | normal | CC: | acpi-bugzilla, andi-bz |
| Priority: | P2 | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Kernel Version: | 2.4, 2.6 | Subsystem: | |
| Regression: | --- | Bisected commit-id: | |
| Attachments: |
ACPI debug enhancement patch.
revised version |
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There should be a new command line option: acpi_debug=layer1:debuglevel,layer2:debuglevel There should be some way to enable/disable function call tracing for a layer. The default for this should be off unless explicitely enabled. When ACPI_DEBUG is compiled in there should be no more output than without it, all additional output should be keyed on the command line. ACPI_DEBUG should be split into multiple options: an ACPI_LEAN_DEBUG that only enables error/warning output and a ACPI_TRACE_DEBUG that compiles in all the function tracing. This would enable to compile the important debug output code into the production kernel without undue binary size overhead. Created attachment 3471 [details]
ACPI debug enhancement patch.
Andi, I also tried your CONFIG_ACPI_LEAN_DEBUG suggestion. Base on my
investigation, the "trace debug" takes up 1/3 of the total debug information,
about 20k. Since it is not the major part of the debug info, I didn't implement
it.
Sorry didn't see the patch earlier because I wasn't in cc. Did you investigate where the majority of the debug overhead comes from? A bit more light weight debugging would be still nice. The patch looks good for a start. Can you merge it into mainline? A small comment - it would be nicer if the individual levels were ascii strings separated by comma instead of numbers. Could you please change that? Thanks. The ACPI_DEBUG_PRINT macro is called 780 times, most of which use ERROR and INFO severity. TRACE related macros are called 600 times, DUMP macros are rare comparing with first two. I assume the ascii requirement is for boot cmdline, because the /proc interface will print more meaningful debug levels. There are now 30 debug_levels, it could be a long string if one wants to enable many levels with ascii. Right? Created attachment 3478 [details]
revised version
add ACPI_ALL_DRIVERS support for debug_layer
i'm okay with having numbers on the command line, particularly in light of how many bits we have -- we'd have to invent a new language just to describe them all. Also, these are debug flags, which end-users are going to use only under the guidance of some technical person who can tell them what flags to type in. Ditto for the /proc/ interface. shipped in 2.6.9 closing |
What we need: 1. less expensive build-time option than CONFIG_ACPI_DEBUG that distros can ship enabled by default. 2. ability to set acpi debug flags on boot cmdline particularly to debug boot failures 3. better /proc support ala ipw2100 for better control over run-time debugging. certainly we need to do away with the current hard-coded invocation of acpi_set_debug() from acpi_init().