Re: [Linux-fbdev-users] PATCH: vga console tweak
From: James Simmons <hidden>
Date: 2005-05-14 00:20:46
The attached patch puts a hard 32k ceiling on copies to and from the VGA VRAM space. This bug was discovered with a 1920x1440 framebuffer console - before switching from VGA, the console is expanded to 240 cols x 90 rows, equaling a screenbuf_size of 43200 bytes. Since the VGA VRAM space is only 32k bytes big, calling vgacon_save_screen during the console transfer copied in a good chunk of the video BIOS living at 0xc0000 too, resulting in some very purty colors and characters at the bottom of the new console.
I made the patch a little more flexiable for video size. It is possible to use 64K or even 128K of video memory. So we ask. Could you give my patch a run. Its against Linus latest tree.
--- linus-2.6/drivers/video/console/vgacon.c 2005-05-10 08:39:33.000000000 -0700
+++ fbdev-2.6/drivers/video/console/vgacon.c 2005-05-13 17:11:37.000000000 -0700@@ -95,6 +95,7 @@ static unsigned long vgacon_uni_pagedir[ /* Description of the hardware situation */ static unsigned long vga_vram_base; /* Base of video memory */ static unsigned long vga_vram_end; /* End of video memory */ +static int vga_vram_size; /* Size of video memory */ static u16 vga_video_port_reg; /* Video register select port */ static u16 vga_video_port_val; /* Video register value port */ static unsigned int vga_video_num_columns; /* Number of text columns */
@@ -288,6 +289,7 @@ static const char __init *vgacon_startup vga_vram_base = VGA_MAP_MEM(vga_vram_base); vga_vram_end = VGA_MAP_MEM(vga_vram_end); + vga_vram_size = vga_vram_end - vga_vram_base; /* * Find out if there is a graphics card present.
@@ -504,9 +506,13 @@ static int vgacon_switch(struct vc_data */ vga_video_num_columns = c->vc_cols; vga_video_num_lines = c->vc_rows; + + /* We can only copy out the size of the video buffer here, + * otherwise we get into VGA BIOS */ + if (!vga_is_gfx) scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf, - c->vc_screenbuf_size); + c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size); return 0; /* Redrawing not needed */ }
@@ -961,7 +967,6 @@ static int vgacon_scrolldelta(struct vc_ if (!lines) /* Turn scrollback off */ c->vc_visible_origin = c->vc_origin; else { - int vram_size = vga_vram_end - vga_vram_base; int margin = c->vc_size_row * 4; int ul, we, p, st;
@@ -971,7 +976,7 @@ static int vgacon_scrolldelta(struct vc_ we = vga_rolled_over + c->vc_size_row; } else { ul = 0; - we = vram_size; + we = vga_vram_size; } p = (c->vc_visible_origin - vga_vram_base - ul + we) % we + lines * c->vc_size_row;
@@ -1012,9 +1017,13 @@ static void vgacon_save_screen(struct vc c->vc_x = ORIG_X; c->vc_y = ORIG_Y; } + + /* We can't copy in more then the size of the video buffer, + * or we'll be copying in VGA BIOS */ + if (!vga_is_gfx) scr_memcpyw((u16 *) c->vc_screenbuf, (u16 *) c->vc_origin, - c->vc_screenbuf_size); + c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size); } static int vgacon_scroll(struct vc_data *c, int t, int b, int dir, -------------------------------------------------------
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