Default timings in vga16fb driver

[Martin Wilck <martin.wilck@fujitsu-siemens.com>]

Hello,

I am wondering about the standard mode timings for the 640x480@60 mode 
in vga16fb driver (vga16fb_defined):

	.pixclock	= 39721,
	.left_margin	= 48,
	.right_margin	= 16,
	.upper_margin	= 39,
	.lower_margin	= 8,
	.hsync_len 	= 96,
	.vsync_len	= 2,
	.vmode		= FB_VMODE_NONINTERLACED,

IMO this corresponds to a total screen height of 529 which is different 
from the value 525 which is normally used (eg in X Windows). What is the 
reason for this? Is it possible that the value for "upper_margin" should 
be 35 rather than 39?

I am asking because we have encountered a video device that obviously 
has problems displaying the standard mode of the vga16fb driver.

More detail:

Unless I'm  mistaken, the above translates into an XFree86 modeline
   ModeLine "640x480" 25.175 640 656 752 800 480 488 490 529

The standard XFree86 modeline for this mode, however, looks like this:
(same in drivers/video/modedb.c)
   ModeLine "640x480" 25.175 640 664 760 800 480 491 493 525

The description at http://www.epanorama.net/documents/pc/vga_timing.html.
would suggest:
   ModeLine "640x480" 25.175 640 656 752 800 480 490 492 525

I apologize if I'm overlooking something.

Best regards,
Martin

--
Martin Wilck                Phone: +49 5251 8 15113
Fujitsu Siemens Computers   Fax:   +49 5251 8 20409
Heinz-Nixdorf-Ring 1        mailto:Martin.Wilck@Fujitsu-Siemens.com
D-33106 Paderborn           http://www.fujitsu-siemens.com/primergy



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