Re: [PATCH] vgacon: Workaround for resize bug in some chipsets

["Jason Dravet" <dravet@hotmail.com>]

> From: Samuel Thibault <samuel.thibault@ens-lyon.org>
> To: Jason Dravet <dravet@hotmail.com>
> CC: 7eggert@gmx.de, adaplas@gmail.com, torvalds@osdl.org, 
> akpm@osdl.org,davej@redhat.com, linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] vgacon: Workaround for resize bug in some chipsets
> Date: Thu, 17 Nov 2005 00:52:16 +0100
>
> Hi,
>
> The following patch should correct the issue:
>
> When doublescan mode is in use, scanlines must be doubled.
>
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
>
> --- drivers/video/console/vgacon.c.orig	2005-11-17 00:40:02.000000000 +0100
> +++ drivers/video/console/vgacon.c	2005-11-17 00:42:27.000000000 +0100
> @@ -502,10 +502,16 @@
>  {
>  	unsigned long flags;
>  	unsigned int scanlines = height * c->vc_font.height;
> -	u8 scanlines_lo, r7, vsync_end, mode;
> +	u8 scanlines_lo, r7, vsync_end, mode, max_scan;
>
>  	spin_lock_irqsave(&vga_lock, flags);
>
> +	outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);
> +	max_scan = inb_p(vga_video_port_val);
> +
> +	if (max_scan & 0x80)
> +		scanlines <<= 1;
> +
>  	outb_p(VGA_CRTC_MODE, vga_video_port_reg);
>  	mode = inb_p(vga_video_port_val);

The patch does fix my problem.  Thank you Samuel.  I really appreciate the 
work you and Antonino have done on this issue.  I look forward to seeing 
this patch in the mainline.

Thanks again,
Jason Dravet


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