Date:   Wed, 12 Apr 2017 16:42:09 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Oleksandr Andrushchenko <andr2000@...il.com>,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
        linux-input@...r.kernel.org
Cc:     boris.ostrovsky@...cle.com, dmitry.torokhov@...il.com
Subject: Re: [PATCH v3] xen,input: add xen-kbdfront module parameter for
 setting resolution

On 12/04/17 16:13, Oleksandr Andrushchenko wrote:
> 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@...e.com>
>> ---
>> 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@...m.com>

Thanks.

> 
> 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?

Mention the dependency in the commit message below a marker line
containing only '---' (without the "'"). Probably there will be at
least a few review rounds so the patches you are depending on have
a chance to make it into the kernel until your patches are applied.
In case your code is perfect from the beginning we can coordinate
the pull requests to be in correct sequence. :-)


Juergen

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