Rework the way that kernel log messages are rate-limited or suppressed
while running the cs_dsp KUnit tests.
Under normal conditions cs_dsp doesn't produce an unreasonable number of
log messages, and state changes are relatively infrequent. But the KUnit
tests run through a very large number of test cases, especially error
cases, and this produces an unusually large amount of log output from
cs_dsp.
The original fix for this in commit 10db9f6899 ("firmware: cs_dsp:
rate-limit log messages in KUnit builds") was effective but not pretty.
It involved different definitions of the log macros for KUnit and
not-KUnit builds, and exported variables for the KUnit tests to disable
log messages. I would have preferred to turn the log macros into real
functions that can contain a KUNIT_STATIC_STUB_REDIRECT(), but the
dev_xxx() macros don't have a version that take va_args, so they can't
be wrapped by a function.
This patch enables the use of a KUNIT_STATIC_STUB_REDIRECT() instead
of exported variables, and avoids the need for different definitions of
the debug macros in KUnit and not-KUnit builds.
- A new function cs_dsp_can_emit_message() returns true if the
messages can be emitted to the kernel log. In a normal not-KUnit build
this function collapses to simply returning true. In KUnit builds it
will rate-limit output, and this uses a single static rate limiter so
it limits the overall rate across all cs_dsp log messages. The KUnit
test can redirect it to change the suppression behavior.
- The cs_dsp debug message macros are changed to only call the dev_xxx()
if cs_dsp_can_emit_message() returns true. These are still macros so
there is no problem wrapping the dev_xxx(). For a normal not-KUnit
build cs_dsp_can_emit_message() always returns true so these macros
simplify down to being identical to calling dev_xxx() directly.
- The KUnit tests that cause a lot of cs_dsp messages now redirect
cs_dsp_can_emit_message() to a local function. This returns false
to suppress cs_dsp messages, unless DEBUG is defined for that test.
I have checked that for a x86_64 production (non-KUnit) build the
disassembled cs_dsp.o is identical to what was generated from the
original code. So the complier is correctly simplifying the
cs_dsp_can_emit_message() and macros down to only the call to dev_xxx().
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20260310130343.1791951-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Use the dev_*_ratelimit() macros if the cs_dsp KUnit tests are enabled
in the build, and allow the KUnit tests to disable message output.
Some of the KUnit tests cause a very large number of log messages from
cs_dsp, because the tests perform many different test cases. This could
cause some lines to be dropped from the kernel log. Dropped lines can
prevent the KUnit wrappers from parsing the ktap output in the dmesg log.
The KUnit builds of cs_dsp export three bools that the KUnit tests can
use to entirely disable log output of err, warn and info messages. Some
tests have been updated to use this, replacing the previous fudge of a
usleep() in the exit handler of each test. We don't necessarily want to
disable all log messages if they aren't expected to be excessive,
so the rate-limiting allows leaving some logging enabled.
The rate-limited macros are not used in normal builds because it is not
appropriate to rate-limit every message. That could cause important
messages to be dropped, and there wouldn't be such a high rate of
messages in normal operation.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/linux-sound/af393f08-facb-4c44-a054-1f61254803ec@opensource.cirrus.com/T/#t
Fixes: cd8c058499 ("firmware: cs_dsp: Add KUnit testing of bin error cases")
Link: https://patch.msgid.link/20260130171256.863152-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
