From: Karel Kulhavy (clock@atrey.karlin.mff.cuni.cz)
Date: Mon 06 Mar 2000 - 23:15:55 IST
Hi I experimented with writing a SVGAlib picture viewer (download at ftp://atrey.karlin.mff.cuni.cz/pub/local/clock/wb0) and realized that SVGAlib doesn't restore the setting of which 64K page is mapped to 0xa0000 for older SVGA'a that use this stupid paging scheme. It occured in a way such that I made my browser slowly download a picture which was incrementally displayed onscreen. During the display I switched to another VT and back. The picture was there OK but continued to draw at absolutely weird position, I guess that in page zero. After about 64K it jumped to the right page and remained there. When i pressed "redraw" in my browser, picure jumped to be absolutely OK. I use my own VT switch code copied from SVGAlib inside the browser. My card is Western Digital WD90c31 with 512k memory and the mode was 800x600x256colours. When I tried the browser on good card with linear framebuffer (S3 Trio3D/2X chipset 368 2xAGP 4MB SGRAM), the browser didn't do it. Shall my code prove to be defective or is it a bug in SVGAlib, or is it simply a SVGAlib's feature that restoration of page setting is not guaranteed? Best regards, Karel Kulhavy
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