Subject: Re: server X
From: [email-masked] (Larry Hall)

24 Sep 1998 11:53:41 -0700
Message-ID: <[email-masked]>
References: <001201bde6b5$dae0da40$1f105c18@B0B>
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To: "GoatCheez" <[email-masked]>, "Jeff Sturm" <[email-masked]>,
        "David Fox" <[email-masked]>
Cc: <[email-masked]>

The problem is DirectX versions don't get updated on NT with the same
alacrity that they do on 9x.  I think the currently supported(?) version
is DirectX 3 on NT.  Here is one place where capabilities in 9x outstrip
those in NT!  So a DirectX approach will not allow an XFree86 "port" to 
address the need of both 9x and NT users at this time...

Larry Hall                              [email-masked]
RFK Partners, Inc.                      (781) 239-1053
8 Grove Street                          (781) 239-1655 - FAX
Wellesley, MA  02482-7797               http://www.rfk.com

At 10:48 PM 9/22/98 -0700, GoatCheez wrote:
>    In the most recent version of DirectX (6), another version of DirectDraw
>was implemented(4). This version allows the locking and unlocking of a video
>surface without the rest of the windows system to stop... in other words,
>accessing the cideo memory directly isn't as scary as it previously was.
>Before, when someone would lock the video memory, the entire cpu would give
>access to only that program running, which made all other applications cease
>untill the surface was unlocked. It was done for backwards compatablility or
>something, but in DirectX6 there's an option to allow the system to respond
>normally. The old system would also not allow debugging because the debugger
>wouldn't be running then the surface was locked. A DirectX  X server would
>be a good idea. The only thing needed is some DirectX programmers that are
>willing to port the XFree86 code... I know a little DirectDraw and would be
>willing to help, but we would need a lot more.
>
>GoatCheez
>[email-masked]
>
>-----Original Message-----
>From: Jeff Sturm <[email-masked]>
>To: David Fox <[email-masked]>
>Cc: <[email-masked]>
>Date: Tuesday, September 22, 1998 7:30 PM
>Subject: Re: server X
>
>
>>David Fox wrote:
>>> Sergey Okhapkin <[email-masked]> writes:
>>> > Porting _Xfree86_ to win32 is a bad idea, because Xfree86 requires
>direct
>>> > video hardware access.
>>>
>>> Could you expand on this further?  Why is direct video hardware access
>>> more of a problem under windows than it is under Unix?
>>
>>(A small clarification to Sergey's post: XFree86 is designed for video
>>framebuffer access.  It need not access video registers directly.
>>Recent work in Linux for example has moved video drivers out of X and
>>into the kernel; X opens the display via the /dev/fb device.)
>>
>>The big difference is that under Unix, the X server controls the entire
>>display.  Under Win32 however, X has to cooperate with the native window
>>subsystem.  I think that precludes an X server from accessing video
>>memory from Win32 (does anyone know otherwise?).  It may be able to
>>write to backing store... I'm not sure if this is better (easier or more
>>efficient, that is) than just translating X drawing requests into GDI
>>requests.
>>
>>If it turns out that the "virtual framebuffer" technique is feasible,
>>I'd contend that the XFree86 source is a better starting point than
>>TOG's X11R6.4, since they have cleaned up and fixed a lot of the cfb
>>code.
>>
>>--
>>Jeff Sturm
>>[email-masked]
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>-
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>
Larry
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