Messages in this thread | | | Date | Wed, 26 Jan 2000 10:13:11 +0200 (EET) | From | Aki M Laukkanen <> | Subject | Re: vm86 in kernel [was: vesafb...] |
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On Tue, 25 Jan 2000, Kendall Bennett wrote: > Yes, I am talking about text framebuffer console acceleration and > mode sets. Graphics mode consoles can benefit tremendously from > hardware accelerated blitting (for scrolling) and hardware > accelerated text rendering for drawing the fonts.
Ok, I'll see what you are getting at considering the statements about XFree 4 modularised driver support later.
Here are some timing results which I consider enlightening. I'll have to say I was surpised. These results were gotten by cycling the available modes in X and panning around in the virtual screen with a mouse.
Name|Time (ms)|Times -------------------------+---------+----- pan_display | 13.587| 268 encode_fix | 0.011| 21 set_var | 464.447| 21
As you can see encode_fix does not call LRMI_int() and the time it takes might be mostly gettimeofday() overhead (I have to change my timing code to use rdtsc some time). However even pan_display which I know to be just a couple of outb-instructions on CT6555x takes 13.5 ms. The time for set_var() which might call SET_MODE, SET_LOGICAL_SCAN_LINE_LENGTH and SET_DISPLAY_START depending of the mode is almost half a seconds. I have to double-check that it does not try to clear the screen by itself but I'm sure I got it right. Scheduling policy of the daemon was SCHED_RR.
> framebuffer console support that can utilise XFree86 4.0 loadable > modules to implement the mode set and blitting functions. Why re- > write code when it could be re-used (even at the binary level!).
Which makes sense. I haven't researched this myself but according to Matan Ziv-Av (svgalib maintainer) supporting XFree 4 loadable modules will not be a easy task. There are apparently hundreds of support functions which these drivers need. > Forget the VBE 3.0 PMI interface functions, at least for now. > Unfortunately a number of well known graphics cards (NVIDIA boards > from Diamond) shipped with a broken VBE 3.0 PMI interface. NVIDIA
I had a feeling that this would be the case. Hence the idea concerning black listing BIOSes. Thanks for the information. I knew that the BIOS of my laptop (Toshiba) would not be alone in this respect. :(
> I will email you copies of the code that you can use, under the GPL > license. Feel free to cut and paste what stuff you need, but make > sure you retain my copyright in your code somewhere.
Thank you. I certainly will.
-- D.
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