From 0aec4867dca149e2049e8439b76bd82ad9dac52c Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Sun, 16 Oct 2005 20:29:22 -0700 Subject: [PATCH] SVGATextMode fix Fix bug 5441. I didn't know about messy programs like svgatextmode... Couldn't this be integrated in some linux/drivers/video/console/svgacon.c ?... So because of the existence of the svgatextmode program, the kernel is not supposed to touch to CRT_OVERFLOW/SYNC_END/DISP/DISP_END/OFFSET ? Disabling the check in vgacon_resize() might help indeed, but I'm really not sure whether it will work for any chipset: in my patch, CRT registers are set at each console switch, since stty rows/cols apply to consoles separately... The attached solution is to keep the test, but if it fails, we assume that the caller knows what it does (i.e. it is svgatextmode) and then disable any further call to vgacon_doresize. Svgatextmode is usually used to _expand_ the display, not to shrink it. And it is harmless in the case of a too big stty rows/cols: the display will just be cropped. I tested it on my laptop, and it works fine with svgatextmode. A better solution would be that svgatextmode explicitely tells the kernel not to care about video timing, but for this an interface needs be defined and svgatextmode be patched. Signed-off-by: Samuel Thibault Cc: "Antonino A. Daplas" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/console/vgacon.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c index 6ef6f7760e47..809fee2140ac 100644 --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c @@ -565,7 +565,11 @@ static int vgacon_switch(struct vc_data *c) scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf, c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size); - vgacon_doresize(c, c->vc_cols, c->vc_rows); + if (!(vga_video_num_columns % 2) && + vga_video_num_columns <= ORIG_VIDEO_COLS && + vga_video_num_lines <= (ORIG_VIDEO_LINES * + vga_default_font_height) / c->vc_font.height) + vgacon_doresize(c, c->vc_cols, c->vc_rows); } return 0; /* Redrawing not needed */ @@ -1023,7 +1027,8 @@ static int vgacon_resize(struct vc_data *c, unsigned int width, if (width % 2 || width > ORIG_VIDEO_COLS || height > (ORIG_VIDEO_LINES * vga_default_font_height)/ c->vc_font.height) - return -EINVAL; + /* let svgatextmode tinker with video timings */ + return 0; if (CON_IS_VISIBLE(c) && !vga_is_gfx) /* who knows */ vgacon_doresize(c, width, height); -- cgit v1.2.3