Merge tag 'usb-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB/PHY updates from Greg KH:
 "Here is the big USB/PHY driver patches for 4.20-rc1

  Lots of USB changes in here, primarily in these areas:

   - typec updates and new drivers

   - new PHY drivers

   - dwc2 driver updates and additions (this old core keeps getting
     added to new devices.)

   - usbtmc major update based on the industry group coming together and
     working to add new features and performance to the driver.

   - USB gadget additions for new features

   - USB gadget configfs updates

   - chipidea driver updates

   - other USB gadget updates

   - USB serial driver updates

   - renesas driver updates

   - xhci driver updates

   - other tiny USB driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (229 commits)
  usb: phy: ab8500: silence some uninitialized variable warnings
  usb: xhci: tegra: Add genpd support
  usb: xhci: tegra: Power-off power-domains on removal
  usbip:vudc: BUG kmalloc-2048 (Not tainted): Poison overwritten
  usbip: tools: fix atoi() on non-null terminated string
  USB: misc: appledisplay: fix backlight update_status return code
  phy: phy-pxa-usb: add a new driver
  usb: host: add DT bindings for faraday fotg2
  usb: host: ohci-at91: fix request of irq for optional gpio
  usb/early: remove set but not used variable 'remain_length'
  usb: typec: Fix copy/paste on typec_set_vconn_role() kerneldoc
  usb: typec: tcpm: Report back negotiated PPS voltage and current
  USB: core: remove set but not used variable 'udev'
  usb: core: fix memory leak on port_dev_path allocation
  USB: net2280: Remove ->disconnect() callback from net2280_pullup()
  usb: dwc2: disable power_down on rockchip devices
  usb: gadget: udc: renesas_usb3: add support for r8a77990
  dt-bindings: usb: renesas_usb3: add bindings for r8a77990
  usb: gadget: udc: renesas_usb3: Add r8a774a1 support
  USB: serial: cypress_m8: remove set but not used variable 'iflag'
  ...

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