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Commit d1521260 authored by Samuel Thibault's avatar Samuel Thibault Committed by Linus Torvalds
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[PATCH] vgacon: no vertical resizing on EGA 

EGA boards suck: they mostly have write-only registers.  This is
particularly problematic for the overflow register: for being able to write
to it, we would have to handle vertical sync & such too, which (I'd say)
would potentially break a lot of configurations.  Instead, just disabling
vertical resize for EGA boards is just nice enough (horizontal resize still
works).

Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6106



Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Rafal Olearski <olearski@mail2.kim.net.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fe1db50c

drivers/video/console/vgacon.c

+35 −32
Original line number Diff line number Diff line
@@ -509,18 +509,19 @@ static int vgacon_doresize(struct vc_data *c, 
{

	unsigned long flags;

	unsigned int scanlines = height * c->vc_font.height;

	u8 scanlines_lo, r7, vsync_end, mode, max_scan;

	u8 scanlines_lo = 0, r7 = 0, vsync_end = 0, mode, max_scan;



	spin_lock_irqsave(&vga_lock, flags);



	vgacon_xres = width * VGA_FONTWIDTH;

	vgacon_yres = height * c->vc_font.height;

	if (vga_video_type >= VIDEO_TYPE_VGAC) {

		outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);

		max_scan = inb_p(vga_video_port_val);



		if (max_scan & 0x80)

			scanlines <<= 1;



	vgacon_xres = width * VGA_FONTWIDTH;

	vgacon_yres = height * c->vc_font.height;

		outb_p(VGA_CRTC_MODE, vga_video_port_reg);

		mode = inb_p(vga_video_port_val);
@@ -543,12 +544,14 @@ static int vgacon_doresize(struct vc_data *c, 
		vsync_end = inb_p(vga_video_port_val);

		outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);

		outb_p(vsync_end & ~0x80, vga_video_port_val);

	}



	outb_p(VGA_CRTC_H_DISP, vga_video_port_reg);

	outb_p(width - 1, vga_video_port_val);

	outb_p(VGA_CRTC_OFFSET, vga_video_port_reg);

	outb_p(width >> 1, vga_video_port_val);



	if (vga_video_type >= VIDEO_TYPE_VGAC) {

		outb_p(VGA_CRTC_V_DISP_END, vga_video_port_reg);

		outb_p(scanlines_lo, vga_video_port_val);

		outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
@@ -557,9 +560,9 @@ static int vgacon_doresize(struct vc_data *c, 
		/* reprotect registers */

		outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);

		outb_p(vsync_end, vga_video_port_val);

	}



	spin_unlock_irqrestore(&vga_lock, flags);



	return 0;

}