lkml.org 
[lkml]   [2015]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/6] ALSA: line6: Add delay before reading status
At Tue, 10 Feb 2015 23:03:13 -0600,
Chris Rorvick wrote:
>
> The device indicates the result of a read/write operation by making the
> status available on a subsequent request from the driver. This is not
> ready immediately, though, so the driver is currently slamming the
> device with hundreds of pointless requests before getting the expected
> response. Add a two millisecond delay before each attempt. This is
> approximately the behavior observed with version 4.2.7.1 of the Windows
> driver.
>
> Signed-off-by: Chris Rorvick <chris@rorvick.com>

Applied, thanks.


Takashi

> ---
> sound/usb/line6/driver.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
> index aac1e35..222c14f 100644
> --- a/sound/usb/line6/driver.c
> +++ b/sound/usb/line6/driver.c
> @@ -296,6 +296,8 @@ static void line6_data_received(struct urb *urb)
> line6_start_listen(line6);
> }
>
> +#define LINE6_READ_WRITE_STATUS_DELAY 2 /* milliseconds */
> +
> /*
> Read data from device.
> */
> @@ -319,6 +321,8 @@ int line6_read_data(struct usb_line6 *line6, u16 address, void *data,
>
> /* Wait for data length. We'll get 0xff until length arrives. */
> do {
> + mdelay(LINE6_READ_WRITE_STATUS_DELAY);
> +
> ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
> USB_TYPE_VENDOR | USB_RECIP_DEVICE |
> USB_DIR_IN,
> @@ -376,6 +380,8 @@ int line6_write_data(struct usb_line6 *line6, u16 address, void *data,
> }
>
> do {
> + mdelay(LINE6_READ_WRITE_STATUS_DELAY);
> +
> ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
> 0x67,
> USB_TYPE_VENDOR | USB_RECIP_DEVICE |
> --
> 2.1.0
>


\
 
 \ /
  Last update: 2015-02-11 10:41    [W:0.074 / U:4.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site