On Thu, Aug 01, 2013 at 12:14:18PM -0300, Fabio Estevam wrote:
> Hi Nate,
>
> On Tue, Jul 30, 2013 at 6:33 PM, Stoddard, Nate (GE Healthcare)
> <Nate.Stoddard@xxxxxxxxxx> wrote:
>
> > So you would expect a temporary CPU increase when a device is connected or reset since the scheduler will need to set up when the packets will be transferred. Once this is complete, the CPU should return to a lower amount as
>
> The reset function at drivers/usb/chipidea/core.c has the following:
>
> int hw_device_reset(struct ci_hdrc *ci, u32 mode)
> {
> /* should flush & stop before reset */
> hw_write(ci, OP_ENDPTFLUSH, ~0, ~0);
> hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
>
> hw_write(ci, OP_USBCMD, USBCMD_RST, USBCMD_RST);
> while (hw_read(ci, OP_USBCMD, USBCMD_RST))
> udelay(10); /* not RTOS friendly */
>
> Maybe this udelay is impacting your performance?
>
> It seems that this should be rewritten to avoid the busy loop.
>
No, it is not related to this problem, this function is only called
at device mode. All EHCI related is controlled by EHCI core. Currently,
we still not override anything for host.
--
Best Regards,
Peter Chen
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