kselftest/alsa: Report failures to set the requested channels as skips

If constraint selection gives us a number of channels other than the one
that we asked for that isn't a failure, that is the device implementing
constraints and advertising that it can't support whatever we asked
for. Report such cases as a test skip rather than failure so we don't have
false positives.

Signed-off-by: Mark Brown <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

tools/testing/selftests/alsa/pcm-test.c

···
 	snd_pcm_sframes_t frames;
 	long long ms;
 	long rate, channels, period_size, buffer_size;
+	unsigned int rchannels;
 	unsigned int rrate;
 	snd_pcm_uframes_t rperiod_size, rbuffer_size, start_threshold;
 	timestamp_t tstamp;
···
 					   snd_pcm_format_name(format), snd_strerror(err));
 		goto __close;
 	}
-	err = snd_pcm_hw_params_set_channels(handle, hw_params, channels);
+	rchannels = channels;
+	err = snd_pcm_hw_params_set_channels_near(handle, hw_params, &rchannels);
 	if (err < 0) {
 		snprintf(msg, sizeof(msg), "snd_pcm_hw_params_set_channels %ld: %s", channels, snd_strerror(err));
+		goto __close;
+	}
+	if (rchannels != channels) {
+		snprintf(msg, sizeof(msg), "channels unsupported %ld != %ld", channels, rchannels);
+		skip = true;
 		goto __close;
 	}
 	rrate = rate;