diff options
Diffstat (limited to 'drivers/usb/core/generic.c')
| -rw-r--r-- | drivers/usb/core/generic.c | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index f713cecc1f41..1ac9c1e5f773 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -118,6 +118,31 @@ int usb_choose_configuration(struct usb_device *udev) continue; } + /* + * Select first configuration as default for audio so that + * devices that don't comply with UAC3 protocol are supported. + * But, still iterate through other configurations and + * select UAC3 compliant config if present. + */ + if (desc && is_audio(desc)) { + /* Always prefer the first found UAC3 config */ + if (is_uac3_config(desc)) { + best = c; + break; + } + + /* If there is no UAC3 config, prefer the first config */ + else if (i == 0) + best = c; + + /* Unconditional continue, because the rest of the code + * in the loop is irrelevant for audio devices, and + * because it can reassign best, which for audio devices + * we don't want. + */ + continue; + } + /* When the first config's first interface is one of Microsoft's * pet nonstandard Ethernet-over-USB protocols, ignore it unless * this kernel has enabled the necessary host side driver. @@ -132,25 +157,6 @@ int usb_choose_configuration(struct usb_device *udev) #endif } - /* - * Select first configuration as default for audio so that - * devices that don't comply with UAC3 protocol are supported. - * But, still iterate through other configurations and - * select UAC3 compliant config if present. - */ - if (i == 0 && num_configs > 1 && desc && is_audio(desc)) { - best = c; - continue; - } - - if (i > 0 && desc && is_audio(desc)) { - if (is_uac3_config(desc)) { - best = c; - break; - } - continue; - } - /* From the remaining configs, choose the first one whose * first interface is for a non-vendor-specific class. * Reason: Linux is more likely to have a class driver |