Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx> writes:
> Change clk_enable/disable() calls to clk_prepare_enable() and
> clk_disable_unprepare().
>
> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
> ---
> drivers/usb/gadget/udc/pxa25x_udc.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/pxa25x_udc.c b/drivers/usb/gadget/udc/pxa25x_udc.c
> index 42f7eeb..e4964ee 100644
> --- a/drivers/usb/gadget/udc/pxa25x_udc.c
> +++ b/drivers/usb/gadget/udc/pxa25x_udc.c
> @@ -103,8 +103,8 @@ static const char ep0name [] = "ep0";
>
> /* IXP doesn't yet support <linux/clk.h> */
> #define clk_get(dev,name) NULL
> -#define clk_enable(clk) do { } while (0)
> -#define clk_disable(clk) do { } while (0)
> +#define clk_prepare_enable(clk) do { } while (0)
> +#define clk_disable_unprepare(clk) do { } while (0)
> #define clk_put(clk) do { } while (0)
>
> #endif
> @@ -932,7 +932,7 @@ static int pullup(struct pxa25x_udc *udc)
> if (!udc->active) {
> udc->active = 1;
> /* Enable clock for USB device */
> - clk_enable(udc->clk);
> + clk_prepare_enable(udc->clk);
Guess what, Russell's remark on i2c and serial made me cross-check. And there
is a case where this will be called in irq context too ...
See :
-> do_IRQ
-> lubbock_vbus_irq()
-> pxa25x_udc_vbus_session()
-> pullup()
-> clk_prepare_enable()
-> CRACK
Note that your patch is not really the faulty one, I think a threaded irq
instead of the "raw" irq should do the trick. And it is granted on UDC api that
vbus function is called in a "sleeping" context (Felipe correct me if I'm
wrong), so a patch to fix this before your current code would be fine.
Cheers.
--
Robert
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