Heiko,
On Fri, Dec 18, 2015 at 10:30 AM, Heiko Stübner
<heiko.stuebner@xxxxxxxxxxxxx> wrote:
> In specific conditions (involving usb hubs) dwc2 devices can create a
> lot of interrupts, even to the point of overwhelming devices running
> at low frequencies. Some devices need to do special clock handling
> at shutdown-time which may bring the system clock below the threshold
> of being able to handle the dwc2 interrupts. Disabling dwc2-irqs
> in a shutdown callbacks prevents reboots/poweroffs from getting stuck
> in such cases.
>
> The hsotg struct already contains an unused irq element, so we can
> just use it to store the irq number for the shutdown callback.
>
> Signed-off-by: Heiko Stuebner <heiko.stuebner@xxxxxxxxxxxxx>
> ---
> I'm also adapting the code on the clock-side to lessen the effects of
> the slow clock (see clk: rockchip: only enter pll slow-mode directly
> before reboots on rk3288), but this patch also fixes the issue of the
> overwhelming irq-number in itself and may be interesting for other/future
> platforms using the dwc2.
>
>
> drivers/usb/dwc2/platform.c | 35 +++++++++++++++++++++++++++--------
> 1 file changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index 39c1cbf..5510d07 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -306,6 +306,25 @@ static int dwc2_driver_remove(struct platform_device *dev)
> return 0;
> }
>
> +/**
> + * dwc2_driver_shutdown() - Called on device shutdown
> + *
> + * @dev: Platform device
> + *
> + * In specific conditions (involving usb hubs) dwc2 devices can create a
> + * lot of interrupts, even to the point of overwhelming devices running
> + * at low frequencies. Some devices need to do special clock handling
> + * at shutdown-time which may bring the system clock below the threshold
> + * of being able to handle the dwc2 interrupts. Disabling dwc2-irqs
> + * prevents reboots/poweroffs from getting stuck in such cases.
> + */
> +static void dwc2_driver_shutdown(struct platform_device *dev)
> +{
> + struct dwc2_hsotg *hsotg = platform_get_drvdata(dev);
> +
> + disable_irq(hsotg->irq);
In one other place I see dwc2 getting the IRQ from the USB HCD
structure. That is:
dwc2_hsotg_to_hcd(hsotg)->irq
I wonder if that would be a good idea to do? Then a future patch
could just remove the unused (and redundant) irq from the hsotg
structure?
Other than that this seems sane to me.
-Doug
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
