On Friday, November 13, 2015 at 09:34:09 PM, Stephen Warren wrote:
> From: Stephen Warren <swar...@nvidia.com>
>
> When CONFIG_SYS_USB_EVENT_POLL_VIA_CONTROL_EP is enabled, use a
> GET_REPORT control transfer to retrieve the initial state of the
> keyboard. This matches the technique used to poll the keyboard state.
> This is useful since it eliminates the remaining use of interrupt
> transfers from the USB keyboard driver, which allows it to work with
> USB HCD that don't support interrupt transfers.
>
> Cc: Hans de Goede <hdego...@redhat.com>
> Signed-off-by: Stephen Warren <swar...@nvidia.com>
> ---
> Are there any disadvantages to using control transfers over interrupt
> transfers? I'm not aware of any, but I assume there must be a reason
> that U-Boot typically uses interrupt transfers.
I initially implemented the control EP polling because I had a keyboard
which had issues with interrupt transfers.
Reviewed-by: Marek Vasut <ma...@denx.de>
> ---
> common/usb_kbd.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/common/usb_kbd.c b/common/usb_kbd.c
> index 95912f99c767..81c4d62c632b 100644
> --- a/common/usb_kbd.c
> +++ b/common/usb_kbd.c
> @@ -475,6 +475,9 @@ static int usb_kbd_probe(struct usb_device *dev,
> unsigned int ifnum) USB_KBD_BOOT_REPORT_SIZE, data->new,
> data->intinterval);
> if (!data->intq) {
> +#elif defined(CONFIG_SYS_USB_EVENT_POLL_VIA_CONTROL_EP)
> + if (usb_get_report(dev, iface->desc.bInterfaceNumber,
> + 1, 0, data->new, USB_KBD_BOOT_REPORT_SIZE) < 0) {
> #else
> if (usb_submit_int_msg(dev, data->intpipe, data->new, data->intpktsize,
> data->intinterval) < 0) {
Best regards,
Marek Vasut
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