Messages in this thread | | | Date | Wed, 23 Dec 2020 09:15:01 -0500 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 5.4 057/130] ALSA: usb-audio: Check valid altsetting at parsing rates for UAC2/3 |
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On Wed, Dec 23, 2020 at 08:09:41AM +0100, Takashi Iwai wrote: >On Wed, 23 Dec 2020 03:17:00 +0100, >Sasha Levin wrote: >> >> From: Takashi Iwai <tiwai@suse.de> >> >> [ Upstream commit 93db51d06b32227319dae2ac289029ccf1b33181 ] >> >> The current driver code assumes blindly that all found sample rates for >> the same endpoint from the UAC2 and UAC3 descriptors can be used no >> matter which altsetting, but actually this was wrong: some devices >> accept only limited sample rates in each altsetting. For determining >> which altsetting supports which rate, we need to verify each sample rate >> and check the validity via UAC2_AS_VAL_ALT_SETTINGS. This control >> reports back the available altsettings as a bitmap. >> >> This patch implements the missing piece above, the verification and >> reconstructs the sample rate tables based on the result. >> >> An open question is how to deal with the altsettings that ended up >> with no valid sample rates after verification. At least, there is a >> device that showed this problem although the sample rates did work in >> the later usage (see bug link). For now, we accept such an altset as >> is, assuming that it's a firmware bug. >> >> Reported-by: Dylan Robinson <dylan_robinson@motu.com> >> Tested-by: Keith Milner <kamilner@superlative.org> >> Tested-by: Dylan Robinson <dylan_robinson@motu.com> >> BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1178203 >> Link: https://lore.kernel.org/r/20201123085347.19667-4-tiwai@suse.de >> Signed-off-by: Takashi Iwai <tiwai@suse.de> >> Signed-off-by: Sasha Levin <sashal@kernel.org> > >Please drop this for 5.4 or older. At least this caused some problem >on 5.3 kernel that confused USB core by some reason while it works >fine with the recent upstream.
Will do, thanks.
-- Thanks, Sasha
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