Re: [PATCH v3] xen,input: add xen-kbdfront module parameter for setting resolution

[Oleksandr Andrushchenko]

Hi, Juergen!


On 04/11/2017 03:30 PM, Juergen Gross wrote:
> Add a parameter for setting the resolution of xen-kbdfront in order to
> be able to cope with a (virtual) frame buffer of arbitrary resolution.
>
> While at it remove the pointless second reading of parameters from
> Xenstore in the device connection phase: all parameters are available
> during device probing already and that is where they should be read.
>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
> V3: - merged the two patches
>      - read Xenstore parameters during probing of the device only
> ---
>   drivers/input/misc/xen-kbdfront.c | 39 ++++++++++++++-------------------------
>   1 file changed, 14 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
> index 3900875dec10..2fc7895373ab 100644
> --- a/drivers/input/misc/xen-kbdfront.c
> +++ b/drivers/input/misc/xen-kbdfront.c
> @@ -41,6 +41,12 @@ struct xenkbd_info {
>   	char phys[32];
>   };
>   
> +enum { KPARAM_X, KPARAM_Y, KPARAM_CNT };
> +static int ptr_size[KPARAM_CNT] = { XENFB_WIDTH, XENFB_HEIGHT };
> +module_param_array(ptr_size, int, NULL, 0444);
> +MODULE_PARM_DESC(ptr_size,
> +	"Pointing device width, height in pixels (default 800,600)");
> +
>   static int xenkbd_remove(struct xenbus_device *);
>   static int xenkbd_connect_backend(struct xenbus_device *, struct xenkbd_info *);
>   static void xenkbd_disconnect_backend(struct xenkbd_info *);
> @@ -128,7 +134,12 @@ static int xenkbd_probe(struct xenbus_device *dev,
>   	if (!info->page)
>   		goto error_nomem;
>   
> +	/* Set input abs params to match backend screen res */
>   	abs = xenbus_read_unsigned(dev->otherend, "feature-abs-pointer", 0);
> +	ptr_size[KPARAM_X] = xenbus_read_unsigned(dev->otherend, "width",
> +						  ptr_size[KPARAM_X]);
> +	ptr_size[KPARAM_Y] = xenbus_read_unsigned(dev->otherend, "height",
> +						  ptr_size[KPARAM_Y]);
>   	if (abs) {
>   		ret = xenbus_write(XBT_NIL, dev->nodename,
>   				   "request-abs-pointer", "1");
> @@ -174,8 +185,8 @@ static int xenkbd_probe(struct xenbus_device *dev,
>   
>   	if (abs) {
>   		__set_bit(EV_ABS, ptr->evbit);
> -		input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
> -		input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
> +		input_set_abs_params(ptr, ABS_X, 0, ptr_size[KPARAM_X], 0, 0);
> +		input_set_abs_params(ptr, ABS_Y, 0, ptr_size[KPARAM_Y], 0, 0);
>   	} else {
>   		input_set_capability(ptr, EV_REL, REL_X);
>   		input_set_capability(ptr, EV_REL, REL_Y);
> @@ -309,9 +320,6 @@ static void xenkbd_disconnect_backend(struct xenkbd_info *info)
>   static void xenkbd_backend_changed(struct xenbus_device *dev,
>   				   enum xenbus_state backend_state)
>   {
> -	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
> -	int ret, val;
> -
>   	switch (backend_state) {
>   	case XenbusStateInitialising:
>   	case XenbusStateInitialised:
> @@ -321,15 +329,6 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
>   		break;
>   
>   	case XenbusStateInitWait:
> -InitWait:
> -		if (xenbus_read_unsigned(info->xbdev->otherend,
> -					 "feature-abs-pointer", 0)) {
> -			ret = xenbus_write(XBT_NIL, info->xbdev->nodename,
> -					   "request-abs-pointer", "1");
> -			if (ret)
> -				pr_warning("xenkbd: can't request abs-pointer");
> -		}
> -
>   		xenbus_switch_state(dev, XenbusStateConnected);
>   		break;
>   
> @@ -340,17 +339,7 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
>   		 * get Connected twice here.
>   		 */
>   		if (dev->state != XenbusStateConnected)
> -			goto InitWait; /* no InitWait seen yet, fudge it */
> -
> -		/* Set input abs params to match backend screen res */
> -		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> -				 "width", "%d", &val) > 0)
> -			input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
> -
> -		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> -				 "height", "%d", &val) > 0)
> -			input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
> -
> +			xenbus_switch_state(dev, XenbusStateConnected);
>   		break;
>   
>   	case XenbusStateClosed:
I have tested this patch and here we go
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

I also tested this with my patches for multi-touch support and almost
ready to push those as well. With this respect, I have a question on
how this can better be done: my patches depend on your patch + they depend
on new kbdif.h queued for Linux 4.12.

What do you guys think would be the best approach for upstreaming
multi-touch then?

Thank you,
Oleksandr