| Message ID | 1418745435-2851-5-git-send-email-octavian.purdila@intel.com |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, Dec 16, 2014 at 05:57:15PM +0200, Octavian Purdila wrote: > Without suspend/resume functionality in the USB driver the USB core > will disconnect and reconnect the DLN2 port and because the GPIO > framework does not yet support removal of an in-use controller a > suspend/resume operation will result in a crash. > > This patch provides suspend and resume functions for the DLN2 driver > so that the above scenario is avoided. > > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> This patch looks good now, but how did you say this device was powered? If powered by vbus you cannot assume that the device maintains it's state over a suspend cycle, something which would complicate matters quite a bit... Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jan 7, 2015 at 11:26 PM, Johan Hovold <johan@kernel.org> wrote: > On Tue, Dec 16, 2014 at 05:57:15PM +0200, Octavian Purdila wrote: >> Without suspend/resume functionality in the USB driver the USB core >> will disconnect and reconnect the DLN2 port and because the GPIO >> framework does not yet support removal of an in-use controller a >> suspend/resume operation will result in a crash. >> >> This patch provides suspend and resume functions for the DLN2 driver >> so that the above scenario is avoided. >> >> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> > > This patch looks good now, but how did you say this device was powered? > > If powered by vbus you cannot assume that the device maintains it's > state over a suspend cycle, something which would complicate matters > quite a bit... > Yes, the device is powered by VBUS. During my tests, depending on the host and USB port, VBUS is sometimes preserved - and this is the case this patch addresses, and sometimes is not, but in that case because no reset_resume routine is implemented the resume path will go through the disconnect/reconnect process. This second case is not addressed by the patch, as I think in this second case fixing the GPIO framework to support the removal of an in-use device is the best way to go. -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 08, 2015 at 02:16:15AM +1300, Octavian Purdila wrote: > On Wed, Jan 7, 2015 at 11:26 PM, Johan Hovold <johan@kernel.org> wrote: > > On Tue, Dec 16, 2014 at 05:57:15PM +0200, Octavian Purdila wrote: > >> Without suspend/resume functionality in the USB driver the USB core > >> will disconnect and reconnect the DLN2 port and because the GPIO > >> framework does not yet support removal of an in-use controller a > >> suspend/resume operation will result in a crash. > >> > >> This patch provides suspend and resume functions for the DLN2 driver > >> so that the above scenario is avoided. > >> > >> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> > > > > This patch looks good now, but how did you say this device was powered? > > > > If powered by vbus you cannot assume that the device maintains it's > > state over a suspend cycle, something which would complicate matters > > quite a bit... > > Yes, the device is powered by VBUS. During my tests, depending on the > host and USB port, VBUS is sometimes preserved - and this is the case > this patch addresses, and sometimes is not, but in that case because > no reset_resume routine is implemented the resume path will go through > the disconnect/reconnect process. Yes, it depends on the host controller and I believe the common case is to drop VBUS. > This second case is not addressed by > the patch, as I think in this second case fixing the GPIO framework to > support the removal of an in-use device is the best way to go. I agree. But please do mention that this case is not handled in the commit message. Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c index 75358d2..f9c4a0b 100644 --- a/drivers/mfd/dln2.c +++ b/drivers/mfd/dln2.c @@ -791,6 +791,24 @@ out_free: return ret; } +static int dln2_suspend(struct usb_interface *iface, pm_message_t message) +{ + struct dln2_dev *dln2 = usb_get_intfdata(iface); + + dln2_stop(dln2); + + return 0; +} + +static int dln2_resume(struct usb_interface *iface) +{ + struct dln2_dev *dln2 = usb_get_intfdata(iface); + + dln2->disconnect = false; + + return dln2_start_rx_urbs(dln2, GFP_NOIO); +} + static const struct usb_device_id dln2_table[] = { { USB_DEVICE(0xa257, 0x2013) }, { } @@ -803,6 +821,8 @@ static struct usb_driver dln2_driver = { .probe = dln2_probe, .disconnect = dln2_disconnect, .id_table = dln2_table, + .suspend = dln2_suspend, + .resume = dln2_resume, }; module_usb_driver(dln2_driver);
Without suspend/resume functionality in the USB driver the USB core will disconnect and reconnect the DLN2 port and because the GPIO framework does not yet support removal of an in-use controller a suspend/resume operation will result in a crash. This patch provides suspend and resume functions for the DLN2 driver so that the above scenario is avoided. Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> --- drivers/mfd/dln2.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)