diff options
Diffstat (limited to 'drivers/usb/core/generic.c')
| -rw-r--r-- | drivers/usb/core/generic.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index bc8242bc4564..356b05c82dbc 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -21,6 +21,7 @@ #include <linux/usb.h> #include <linux/usb/hcd.h> +#include <uapi/linux/usb/audio.h> #include "usb.h" static inline const char *plural(int n) @@ -42,6 +43,16 @@ static int is_activesync(struct usb_interface_descriptor *desc) && desc->bInterfaceProtocol == 1; } +static bool is_audio(struct usb_interface_descriptor *desc) +{ + return desc->bInterfaceClass == USB_CLASS_AUDIO; +} + +static bool is_uac3_config(struct usb_interface_descriptor *desc) +{ + return desc->bInterfaceProtocol == UAC_VERSION_3; +} + int usb_choose_configuration(struct usb_device *udev) { int i; @@ -121,6 +132,22 @@ 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) && is_uac3_config(desc)) { + best = c; + break; + } + /* 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 |