[Fw_Os_Forum] UEFI pre-boot issues with Microsoft surface pro 4

[Venkat Gorla]

Thanks Aaron, that was helpful.

We are currently working on incorporating your suggestions into our design/
code. We will get back to you if we have more questions.

Thanks,
Venkat


On Thu, May 26, 2016 at 10:07 PM, <Aaron.Pop at congatec.com> wrote:

> Hi Venkat,
>
> >>The UEFI specification (2.6) recommends using OpenProtocol in place on
> HandleProtocol. Does it really matter which one we use?
> I don't think this matters for your preboot application.
>
> >>Once we get the absolute pointer protocol interface handle, is there
> any guidance on when to call the Reset() function?
> If you are worried that the device was not initialized or if the device is
> not working as you would expect it to, you can call the reset function.
>
> >>- When calling GetState function on the protocol interface, how do you
> differentiate between finger touch/ press and release events?
> I think you have some assumptions about how the
> EFI_ABSOLUTE_POINTER_PROTOCOL is supposed to work, and I think those
> assumptions are incorrect. In the simplest terms, the absolute pointer
> protocol is going to give you the current position of the pointer device.
>  I don't believe that it was intended to provide information as involved as
> start of touch and end of touch, or anything else that is associated with
> multi touch device.  I think it would be easier if you though of the
> protocol as giving you a snapshot of the current position of the pointer,
> and the current status of the input buttons (if they exist).
>
>
>
>
>
>
>
> From:        Venkat Gorla <venkatagorla at gmail.com>
> To:        fw_os_forum at mailman.uefi.org
> Date:        05/26/2016 12:15 AM
> Subject:        [Fw_Os_Forum] UEFI pre-boot issues with Microsoft surface
> pro 4
> Sent by:        fw_os_forum-bounces at mailman.uefi.org
> ------------------------------
>
>
>
> Hi,
>
> We are facing few issues with the absolute pointer protocol on Microsoft
> surface pro 4 in the UEFI pre-boot environment. So I am sending this email
> looking for some guidance/ recommendations on how to resolve them.
>
> - In order to query the protocol interface handle we are currently calling
> HandleProtocol(). The UEFI specification (2.6) recommends using
> OpenProtocol in place on HandleProtocol. Does it really matter which one we
> use?
> - Once we get the absolute pointer protocol interface handle, is there any
> guidance on when to call the Reset() function? We are seeing inconsistent
> behavior with the Reset function on different hardware models such as
> Microsoft surface pro 1 and pro 3.
> - For example, on one model calling Reset is giving the desired behavior
> while on the other model, not calling it is working.
>
> - When calling GetState function on the protocol interface, how do you
> differentiate between finger touch/ press and release events?
> This is what we are currently doing in our code, pseudo code:
>
> while (true)
> {
>     status = BS->WaitForEvent(<Array containing "WaitForInput" event of
> the protocol interface>);
>
>     if (status is successful)
>     {
>         EFI_ABSOLUTE_POINTER_STATE PointerState;
>         status = GetState(pAbsolutePointerProtocol, &PointerState);
>
>         // Check return value of GetState and process the touch/ release
> event.
>         if (PointerState.ActiveButtons & EFI_ABSP_TouchActive)
>         {
>             // This is the finger touch/ press event.
>         }
>         else if (PointerState.ActiveButtons & EFI_ABS_AltActive)
>         {
>             // We ignore this event.
>         }
>         else
>         {
>             // This is the finger release event.
>         }
>     }
> }
>
> - Our expectation is that every time you touch and release, we should be
> getting *two* events that get processed by our code.
> - However on Microsoft surface pro 4, we are not always getting the touch
> and release events in pairs and that is throwing off our code.
>
> - Looking at the pseudo code is there something that is missing that could
> be causing this behavior?
> - Additionally are there any known touch related issues with surface pro 4
> and is there any specific guidance on how to resolve them?
>
> Please let me know if you need any additional info to help answer my
> questions.
>
> Thanks,
>     Venkat
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