Hi Mark,
On Tue, Feb 01, 2022 at 03:15:51PM +0000, Mark Brown wrote:
Add some coverage of event generation to mixer-test. Rather than doing a separate set of writes designed to trigger events we add a step to the existing write_and_verify() which checks to see if the value we read back from non-volatile controls matches the value before writing and that an event is or isn't generated as appropriate. The "tests" for events then simply check that no spurious or missing events were detected. This avoids needing further logic to generate appropriate values for each control type and maximises coverage.
When checking for events we use a timeout of 0. This relies on the kernel generating any event prior to returning to userspace when setting a control. That is currently the case and it is difficult to see it changing, if it does the test will need to be updated. Using a delay of 0 means that we don't slow things down unduly when checking for no event or when events fail to be generated.
We don't check behaviour for volatile controls since we can't tell what the behaviour is supposed to be for any given control.
Signed-off-by: Mark Brown broonie@kernel.org
tools/testing/selftests/alsa/mixer-test.c | 148 +++++++++++++++++++++- 1 file changed, 145 insertions(+), 3 deletions(-)
I'm still under reviewing your patch, while I have a slight concern about the evaluation of 'struct snd_ctl_event.data.elem.id.numid'.
diff --git a/tools/testing/selftests/alsa/mixer-test.c b/tools/testing/selftests/alsa/mixer-test.c index 0e88f4f3d802..42cf3b724586 100644 --- a/tools/testing/selftests/alsa/mixer-test.c +++ b/tools/testing/selftests/alsa/mixer-test.c ... +/*
- Block for up to timeout ms for an event, returns a negative value
- on error, 0 for no event and 1 for an event.
- */
+int wait_for_event(struct ctl_data *ctl, int timeout) +{ ...
/* The ID returned from the event is 1 less than numid */mask = snd_ctl_event_elem_get_mask(event);ev_id = snd_ctl_event_elem_get_numid(event);if (ev_id != ctl->elem + 1) {ksft_print_msg("Event for unexpected ctl %s\n",snd_ctl_event_elem_get_name(event));continue;}- } while ((mask & SND_CTL_EVENT_MASK_VALUE) != SND_CTL_EVENT_MASK_VALUE);
- return 1;
+}
As long as I know, the design of ALSA control core just exposes the numeric identification of a control element issued for notification in 'snd_ctl_event' structure. On the other hand, the above evaluation expects decremented value against position of queried list structure has come.
I note that current design of ALSA control core is: * 1 is selected for numeric identification of the first element in the first element set added to sound card. * at removal of element set, the series of assigned numeric identification becomes blank (coded as hole). * Userspace application can always add/remove element set to the card. * the position of element in queried list structure does not necessarily corresponds to numeric identification even if decremented by 1 due to the hole.
Of cource, I can see the decremented-by-1 comparison covers the most cases in which developer requires the test (excluding the case of user-defined control element set), while we can use numid value got from 'id' field of 'ctl_data' structure for the comparison. I think the alternative way has fewer problems than the decremented-by-1 comparison based on the rough assumption against the design.
Regards
Takashi Sakamoto