Re: [Qemu-devel] [PATCH] adb: change handler only when recognized

[Programmingkid]

On Mar 12, 2016, at 12:44 PM, Hervé Poussineau wrote:

> Le 12/03/2016 16:24, Mark Cave-Ayland a écrit :
>> On 12/03/16 13:38, Hervé Poussineau wrote:
>> 
>>> ADB devices must take new handler into account only when they recognize it.
>>> This lets operating systems probe for valid/invalid handles, to know device 
>>> capabilities.
>>> 
>>> Add a FIXME in keyboard handler, which should use a different translation
>>> table depending of the selected handler.
>>> 
>>> Signed-off-by: Hervé Poussineau <address@hidden>
>> 
>> Interesting. Can you explain a bit more about which OSs this patch
>> affects and the symptoms it alleviates?
> 
> Here is a small list of handlers requested by some operating systems without 
> the patch
> HelenOS               kbd=1 mouse=2
> MacOS 9               kbd=1 mouse=0xc (what is 0xc?)
> Linux                 kbd=3 mouse=4
> 
> Here is a small list of handlers requested by some operating systems with the 
> patch
> HelenOS       kbd=1 mouse=2
> MacOS 9       kbd=1 mouse=2
> Linux                 kbd=3 mouse=2
> 
> 
> I have no example of current problem with the keyboard part. However, I 
> suspect it may be related some
> problems John is seeing on some operating systems, as handler 1 and 2/3 must 
> not use the same
> translation table.
> Note that MacOS 9 uses handler 1 (Apple Standard Keyboard), while Linux uses 
> handler 3 (Apple Extended Keyboard LShift != RShift).
> 
> On mouse part, operating systems (like MacOS or Linux) try to probe the mouse 
> model by testing
> different handlers, and see which ones are accepted.
> On Linux, the handler 1 and 2 have a 3 bytes protocol, while the handler 4 
> has a 4 bytes protocol.
> Correctly supporting protocol 4 will be required to handle 3-button mice.
> 
> Hervé

Very interesting. Thank you for this information. So it sounds like the keys 
should change in the keyboard array with respect to the value of kbd. It would 
have to happen during runtime. Do you have any documentation related to your 
handler code? Particularly what keys are and not available for a particular 
handler/keyboard.