4.19-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum oneukum@suse.com
commit f17c34ffc792bbb520e4b61baa16b6cfc7d44b13 upstream.
The OTG 1.3 spec has the feature A_ALT_HNP_SUPPORT, which tells a device that it is connected to the wrong port. Some devices refuse to operate if you enable that feature, because it indicates to them that they ought to request to be connected to another port.
According to the spec this feature may be used based only the following three conditions:
6.5.3 a_alt_hnp_support Setting this feature indicates to the B-device that it is connected to an A-device port that is not capable of HNP, but that the A-device does have an alternate port that is capable of HNP. The A-device is required to set this feature under the following conditions: • the A-device has multiple receptacles • the A-device port that connects to the B-device does not support HNP • the A-device has another port that does support HNP
A check for the third and first condition is missing. Add it.
Signed-off-by: Oliver Neukum oneukum@suse.com Cc: stable stable@kernel.org Fixes: 7d2d641c44269 ("usb: otg: don't set a_alt_hnp_support feature for OTG 2.0 device") Link: https://lore.kernel.org/r/20240122153545.12284-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/core/hub.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-)
--- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2331,17 +2331,25 @@ static int usb_enumerate_device_otg(stru } } else if (desc->bLength == sizeof (struct usb_otg_descriptor)) { - /* Set a_alt_hnp_support for legacy otg device */ - err = usb_control_msg(udev, - usb_sndctrlpipe(udev, 0), - USB_REQ_SET_FEATURE, 0, - USB_DEVICE_A_ALT_HNP_SUPPORT, - 0, NULL, 0, - USB_CTRL_SET_TIMEOUT); - if (err < 0) - dev_err(&udev->dev, - "set a_alt_hnp_support failed: %d\n", - err); + /* + * We are operating on a legacy OTP device + * These should be told that they are operating + * on the wrong port if we have another port that does + * support HNP + */ + if (bus->otg_port != 0) { + /* Set a_alt_hnp_support for legacy otg device */ + err = usb_control_msg(udev, + usb_sndctrlpipe(udev, 0), + USB_REQ_SET_FEATURE, 0, + USB_DEVICE_A_ALT_HNP_SUPPORT, + 0, NULL, 0, + USB_CTRL_SET_TIMEOUT); + if (err < 0) + dev_err(&udev->dev, + "set a_alt_hnp_support failed: %d\n", + err); + } } } #endif