From: Bjørn Mork bjorn@mork.no
[ Upstream commit 93725149794d3d418cf1eddcae60c7b536c5faa1 ]
MDM9x30 based modems appear to go into a deeper sleep when suspended without "Remote Wakeup" enabled. The QMI interface will not respond unless a "set DTR" control request is sent on resume. The effect is similar to a QMI_CTL SYNC request, resetting (some of) the firmware state.
We allow userspace sessions to span multiple character device open/close sequences. This means that userspace can depend on firmware state while both the netdev and the character device are closed. We have disabled "needs_remote_wakeup" at this point to allow devices without remote wakeup support to be auto-suspended.
To make sure the MDM9x30 keeps firmware state, we need to keep "needs_remote_wakeup" always set. We also need to issue a "set DTR" request to enable the QMI interface.
Signed-off-by: Bjørn Mork bjorn@mork.no Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/qmi_wwan.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c index 4391430e25273..b8b15deb94bdb 100644 --- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c @@ -223,6 +223,20 @@ err: return rv; }
+/* Send CDC SetControlLineState request, setting or clearing the DTR. + * "Required for Autoconnect and 9x30 to wake up" according to the + * GobiNet driver. The requirement has been verified on an MDM9230 + * based Sierra Wireless MC7455 + */ +static int qmi_wwan_change_dtr(struct usbnet *dev, bool on) +{ + u8 intf = dev->intf->cur_altsetting->desc.bInterfaceNumber; + + return usbnet_write_cmd(dev, USB_CDC_REQ_SET_CONTROL_LINE_STATE, + USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE, + on ? 0x01 : 0x00, intf, NULL, 0); +} + static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf) { int status = -1; @@ -280,6 +294,24 @@ static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf) usb_driver_release_interface(driver, info->data); }
+ /* disabling remote wakeup on MDM9x30 devices has the same + * effect as clearing DTR. The device will not respond to QMI + * requests until we set DTR again. This is similar to a + * QMI_CTL SYNC request, clearing a lot of firmware state + * including the client ID allocations. + * + * Our usage model allows a session to span multiple + * open/close events, so we must prevent the firmware from + * clearing out state the clients might need. + * + * MDM9x30 is the first QMI chipset with USB3 support. Abuse + * this fact to enable the quirk. + */ + if (le16_to_cpu(dev->udev->descriptor.bcdUSB) >= 0x0201) { + qmi_wwan_manage_power(dev, 1); + qmi_wwan_change_dtr(dev, true); + } + /* Never use the same address on both ends of the link, even if the * buggy firmware told us to. Or, if device is assigned the well-known * buggy firmware MAC address, replace it with a random address, @@ -307,6 +339,12 @@ static void qmi_wwan_unbind(struct usbnet *dev, struct usb_interface *intf) if (info->subdriver && info->subdriver->disconnect) info->subdriver->disconnect(info->control);
+ /* disable MDM9x30 quirk */ + if (le16_to_cpu(dev->udev->descriptor.bcdUSB) >= 0x0201) { + qmi_wwan_change_dtr(dev, false); + qmi_wwan_manage_power(dev, 0); + } + /* allow user to unbind using either control or data */ if (intf == info->control) other = info->data;