Some USB device / host controller combinations seem to have problems
with Link Power Management. For example, Steinar found that his xHCI
controller wouldn't handle bandwidth calculations correctly for two
video cards simultaneously when LPM was enabled, even though the bus
had plenty of bandwidth available.
This patch introduces a new quirk flag for devices that should remain
disabled for LPM, and creates quirk entries for Steinar's devices.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: Steinar H. Gunderson <sgunderson@xxxxxxxxxxx>
---
[as1786]
drivers/usb/core/hub.c | 7 ++++++-
drivers/usb/core/quirks.c | 6 ++++++
include/linux/usb/quirks.h | 3 +++
3 files changed, 15 insertions(+), 1 deletion(-)
Index: usb-4.3/include/linux/usb/quirks.h
===================================================================
--- usb-4.3.orig/include/linux/usb/quirks.h
+++ usb-4.3/include/linux/usb/quirks.h
@@ -47,4 +47,7 @@
/* device generates spurious wakeup, ignore remote wakeup capability */
#define USB_QUIRK_IGNORE_REMOTE_WAKEUP BIT(9)
+/* device can't handle Link Power Management */
+#define USB_QUIRK_NO_LPM BIT(10)
+
#endif /* __LINUX_USB_QUIRKS_H */
Index: usb-4.3/drivers/usb/core/hub.c
===================================================================
--- usb-4.3.orig/drivers/usb/core/hub.c
+++ usb-4.3/drivers/usb/core/hub.c
@@ -124,6 +124,10 @@ struct usb_hub *usb_hub_to_struct_hub(st
int usb_device_supports_lpm(struct usb_device *udev)
{
+ /* Some devices have trouble with LPM */
+ if (udev->quirks & USB_QUIRK_NO_LPM)
+ return 0;
+
/* USB 2.1 (and greater) devices indicate LPM support through
* their USB 2.0 Extended Capabilities BOS descriptor.
*/
@@ -4503,6 +4507,8 @@ hub_port_init (struct usb_hub *hub, stru
goto fail;
}
+ usb_detect_quirks(udev);
+
if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
retval = usb_get_bos_descriptor(udev);
if (!retval) {
@@ -4701,7 +4707,6 @@ static void hub_port_connect(struct usb_
if (status < 0)
goto loop;
- usb_detect_quirks(udev);
if (udev->quirks & USB_QUIRK_DELAY_INIT)
msleep(1000);
Index: usb-4.3/drivers/usb/core/quirks.c
===================================================================
--- usb-4.3.orig/drivers/usb/core/quirks.c
+++ usb-4.3/drivers/usb/core/quirks.c
@@ -186,6 +186,12 @@ static const struct usb_device_id usb_qu
{ USB_DEVICE(0x1a0a, 0x0200), .driver_info =
USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL },
+ /* Blackmagic Design Intensity Shuttle */
+ { USB_DEVICE(0x1edb, 0xbd3b), .driver_info = USB_QUIRK_NO_LPM },
+
+ /* Blackmagic Design UltraStudio SDI */
+ { USB_DEVICE(0x1edb, 0xbd4f), .driver_info = USB_QUIRK_NO_LPM },
+
{ } /* terminating entry must be last */
};
--
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