Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> writes: > On Fri, Oct 12, 2012 at 10:59:22AM -0700, Kevin Hilman wrote: >> Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> writes: >> >> > On Fri, Oct 12, 2012 at 09:35:54AM -0700, Kevin Hilman wrote: >> >> Sourav <sourav.poddar@xxxxxx> writes: >> >> > diff --git a/drivers/tty/serial/omap-serial.c >> >> > b/drivers/tty/serial/omap-serial.c >> >> > index 6ede6fd..3fbc7f7 100644 >> >> > --- a/drivers/tty/serial/omap-serial.c >> >> > +++ b/drivers/tty/serial/omap-serial.c >> >> > @@ -1414,6 +1414,7 @@ static int __devinit serial_omap_probe(struct >> >> > platform_device *pdev) >> >> > INIT_WORK(&up->qos_work, serial_omap_uart_qos_work); >> >> > >> >> > platform_set_drvdata(pdev, up); >> >> > + pm_runtime_set_active(&pdev->dev); >> >> >> >> NAK. >> >> >> >> This will obviously break platforms where the UARTs are not active >> >> before driver loads. >> > >> > I thought I had proposed a solution for this issue, which was this >> > sequence: >> > >> > omap_device_enable(dev); >> > pm_runtime_set_active(dev); >> > pm_runtime_enable(dev); >> > >> > Yes, I can understand people not liking the omap_device_enable() >> > there, but I also notice that the email suggesting that never got a >> > reply either - not even a "I tried this and it doesn't work" or "it >> > does work". >> >> Yes, that solution would work (though I didn't actually try it.) >> >> However, we can't use omap_device_enable() in the driver. We're trying >> to clean all the drivers of OMAP-specific APIs. That being said, >> something similar could be done in the device/board init code to ensure >> the UART HW is in the state that the driver is expecting it, but again, >> that would just mask the real problem which is that a (re)init of the >> console UART on 2420/n800 is causing output to disappear. > > See my more expansive suggestion just posted. > > Whatever way, this discrepancy between runtime PM state and actual device > state is what is biting you, and it is that which needs fixing. I'm not conviced (yet) that a mismatch is the root cause. Yes, that's what the author of $SUBJECT patch assumed and stated, but I'm not pursuaded. If it's an improperly configured mux issue, then the UART will break whenever the device is actually omap_device_enable'd, whether in the driver or in the bus layer. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
