Re: [PATCH v2] drm/udl: Ensure channel is selected before using the device.

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Aug 22, 2016 at 11:17:34PM +0100, Jamie Lentin wrote:
> Lift configuration command from udlfb. This appears to be essential for
> at least a Rextron VCUD-60, without which no URB communication occurs.
> 
> Signed-off-by: Jamie Lentin <jm@lentin.co.uk>
> ---
> udl_encoder_commit() is too late to do this set up in it seems. This
> setup doesn't need to be performed again after a suspend, although this
> is somewhat academic until I send the patch adding suspend and resume
> functions.
> 
> Tested with a Rextron VCUD-60 attached to a Thinkpad X201s on Linux 4.7.0

Applied to drm-misc, thanks.
-Daniel

> 
> Cheers,
> ---
>  drivers/gpu/drm/udl/udl_main.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
> index 33dbfb2..29f0207 100644
> --- a/drivers/gpu/drm/udl/udl_main.c
> +++ b/drivers/gpu/drm/udl/udl_main.c
> @@ -16,6 +16,8 @@
>  /* -BULK_SIZE as per usb-skeleton. Can we get full page and avoid overhead? */
>  #define BULK_SIZE 512
>  
> +#define NR_USB_REQUEST_CHANNEL 0x12
> +
>  #define MAX_TRANSFER (PAGE_SIZE*16 - BULK_SIZE)
>  #define WRITES_IN_FLIGHT (4)
>  #define MAX_VENDOR_DESCRIPTOR_SIZE 256
> @@ -90,6 +92,26 @@ success:
>  	return true;
>  }
>  
> +/*
> + * Need to ensure a channel is selected before submitting URBs
> + */
> +static int udl_select_std_channel(struct udl_device *udl)
> +{
> +	int ret;
> +	u8 set_def_chn[] = {0x57, 0xCD, 0xDC, 0xA7,
> +			    0x1C, 0x88, 0x5E, 0x15,
> +			    0x60, 0xFE, 0xC6, 0x97,
> +			    0x16, 0x3D, 0x47, 0xF2};
> +
> +	ret = usb_control_msg(udl->udev,
> +			      usb_sndctrlpipe(udl->udev, 0),
> +			      NR_USB_REQUEST_CHANNEL,
> +			      (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
> +			      set_def_chn, sizeof(set_def_chn),
> +			      USB_CTRL_SET_TIMEOUT);
> +	return ret < 0 ? ret : 0;
> +}
> +
>  static void udl_release_urb_work(struct work_struct *work)
>  {
>  	struct urb_node *unode = container_of(work, struct urb_node,
> @@ -301,6 +323,9 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags)
>  		goto err;
>  	}
>  
> +	if (udl_select_std_channel(udl))
> +		DRM_ERROR("Selecting channel failed\n");
> +
>  	if (!udl_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
>  		DRM_ERROR("udl_alloc_urb_list failed\n");
>  		goto err;
> -- 
> 2.8.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch