[haiku-development] Re: Where should video driver test for sufficient memory?

2008/12/17 Gerald Zajac <zajacg@xxxxxxxxxxxxx>:
> Under r28800 I was trying to use an S3 Savage4 video card with 8 MB of
> memory.  Before the virtual height of a display mode was doubled (ie, double
> the actual display height), I had no trouble setting any display mode with
> this video card.  Now if the mode is less than 1280x1024 (eg, 1024x768), an
> error occurs when trying to set the mode to 1280x1024 or any higher mode.
>  The error is "The screen mode could not be set;  General System Error", and
> then the app server seems to hang up.  BTW, all this was done using a color
> depth of 32 bits/pixel.
>
> Currently, the S3 driver tests for sufficient frame buffer memory only in
> the "Set Video Mode" function;  thus, I tried putting code in the "Propose
> Display Mode" function to check for sufficient memory;  however, the same
> results were obtained.  When setting the mode, ProposeDisplayMode() is
> called about 15 times before SetDisplayMode() is called;  however, each time
> ProposeDisplayMode() is called it is called to check mode 640x480 instead of
> the mode that will actually be set;  thus, SetDisplayMode() winds up being
> the only place where the test for sufficient memory is made.  This seems to
> be a bug in the app server.

I actually can't tell anything about your specific problem, I just wanted to
confirm that I have also seen the very same ProposeDisplayMode()-behaviour
when tinkering with the vesa driver. Just to let you know...

Michael

> My question is:  When the app server is fixed so that it handles this
> situation correctly, where should the video driver test for sufficient frame
> buffer memory and what error code should it return?
>
> Should I file a bug report on this problem?
>
>
> Best regards,
> Gerald
>
>
>

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