ALSA: usb-audio: Handle discrete rates properly in hw constraints
In the current code, when the device provides the discrete sample rate tables with unusual sample rates, the driver tries to gather the whole values from the audioformat entries and create a hw-constraint rule to restrict with this single rate list. This is rather inefficient and may overlook the rates that are associated only with the certain audioformat entries. This patch improves the hw constraint setup by rewriting the existing hw_rule_rate(). The discrete sample rates (identified by rate_table and nr_rates of format entry) are checked in the existing hw_rule_rate() instead of extra rules; in the case of discrete rates, the function compares with each rate table entry and calculates the min/max values from there. For the contiguous rates, the behavior doesn't change. Along with it, snd_usb_pcm_check_knot() and snb_usb_substream rate_list field become superfluous, thus those are dropped. Tested-by:Keith Milner <kamilner@superlative.org> Tested-by:
Dylan Robinson <dylan_robinson@motu.com> Link: https://lore.kernel.org/r/20201123085347.19667-2-tiwai@suse.de Signed-off-by:
Takashi Iwai <tiwai@suse.de>
parent
418baf2c
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