* [PATCH 4/9][VESAFB]: Use 8-bit DAC for capable hardware
@ 2004-08-21 12:59 Antonino A. Daplas
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From: Antonino A. Daplas @ 2004-08-21 12:59 UTC (permalink / raw)
To: Andrew Morton; +Cc: Linux Fbdev development list
Hi,
The patch adds the ability for vesafb to switch the DAC from 6-bit to 8-bit
at kernel boot. Besides fixing the failure to draw the 224-color logo, an
8-bit DAC will also provide a wider color range for user applications.
Tony
Signed-off-by: Antonino Daplas <adaplas@pol.net>
---
arch/i386/boot/video.S | 38 +++++++++++++++++++++++++++++-
drivers/video/vesafb.c | 62 +++++++++++++++++++++++--------------------------
2 files changed, 67 insertions(+), 33 deletions(-)
diff -uprN linux-2.6.8.1-mm3-orig/arch/i386/boot/video.S linux-2.6.8.1-mm3/arch/i386/boot/video.S
--- linux-2.6.8.1-mm3-orig/arch/i386/boot/video.S 2004-05-10 10:32:26.000000000 +0800
+++ linux-2.6.8.1-mm3/arch/i386/boot/video.S 2004-08-21 19:02:50.611285656 +0800
@@ -232,6 +232,41 @@ mopar_gr:
xorl %eax, %eax
movw 18(%di), %ax
movl %eax, %fs:(PARAM_LFB_SIZE)
+
+# switching the DAC to 8-bit is for <= 8 bpp only
+ movw %fs:(PARAM_LFB_DEPTH), %ax
+ cmpw $8, %ax
+ jg dac_done
+
+# get DAC switching capability
+ xorl %eax, %eax
+ movb 10(%di), %al
+ testb $1, %al
+ jz dac_set
+
+# attempt to switch DAC to 8-bit
+ movw $0x4f08, %ax
+ movw $0x0800, %bx
+ int $0x10
+ cmpw $0x004f, %ax
+ jne dac_set
+ movb %bh, dac_size # store actual DAC size
+
+dac_set:
+# set color size to DAC size
+ movb dac_size, %al
+ movb %al, %fs:(PARAM_LFB_COLORS+0)
+ movb %al, %fs:(PARAM_LFB_COLORS+2)
+ movb %al, %fs:(PARAM_LFB_COLORS+4)
+ movb %al, %fs:(PARAM_LFB_COLORS+6)
+
+# set color offsets to 0
+ movb $0, %fs:(PARAM_LFB_COLORS+1)
+ movb $0, %fs:(PARAM_LFB_COLORS+3)
+ movb $0, %fs:(PARAM_LFB_COLORS+5)
+ movb $0, %fs:(PARAM_LFB_COLORS+7)
+
+dac_done:
# get protected mode interface informations
movw $0x4f0a, %ax
xorw %bx, %bx
@@ -1929,7 +1964,8 @@ scanning: .byte 0 # Performing mode scan
do_restore: .byte 0 # Screen contents altered during mode change
svga_prefix: .byte VIDEO_FIRST_BIOS>>8 # Default prefix for BIOS modes
graphic_mode: .byte 0 # Graphic mode with a linear frame buffer
-
+dac_size: .byte 6 # DAC bit depth
+
# Status messages
keymsg: .ascii "Press <RETURN> to see video modes available, "
.ascii "<SPACE> to continue or wait 30 secs"
diff -uprN linux-2.6.8.1-mm3-orig/drivers/video/vesafb.c linux-2.6.8.1-mm3/drivers/video/vesafb.c
--- linux-2.6.8.1-mm3-orig/drivers/video/vesafb.c 2004-08-17 21:51:40.000000000 +0800
+++ linux-2.6.8.1-mm3/drivers/video/vesafb.c 2004-08-21 19:02:50.613285352 +0800
@@ -87,15 +87,17 @@ static int vesafb_pan_display(struct fb_
return 0;
}
-static void vesa_setpalette(int regno, unsigned red, unsigned green, unsigned blue)
+static void vesa_setpalette(int regno, unsigned red, unsigned green,
+ unsigned blue, struct fb_var_screeninfo *var)
{
#ifdef __i386__
struct { u_char blue, green, red, pad; } entry;
+ int shift = 16 - var->green.length;
if (pmi_setpal) {
- entry.red = red >> 10;
- entry.green = green >> 10;
- entry.blue = blue >> 10;
+ entry.red = red >> shift;
+ entry.green = green >> shift;
+ entry.blue = blue >> shift;
entry.pad = 0;
__asm__ __volatile__(
"call *(%%esi)"
@@ -109,9 +111,9 @@ static void vesa_setpalette(int regno, u
} else {
/* without protected mode interface, try VGA registers... */
outb_p(regno, dac_reg);
- outb_p(red >> 10, dac_val);
- outb_p(green >> 10, dac_val);
- outb_p(blue >> 10, dac_val);
+ outb_p(red >> shift, dac_val);
+ outb_p(green >> shift, dac_val);
+ outb_p(blue >> shift, dac_val);
}
#endif
}
@@ -132,7 +134,7 @@ static int vesafb_setcolreg(unsigned reg
switch (info->var.bits_per_pixel) {
case 8:
- vesa_setpalette(regno,red,green,blue);
+ vesa_setpalette(regno,red,green,blue, &info->var);
break;
case 16:
if (info->var.red.offset == 10) {
@@ -331,30 +333,26 @@ static int __init vesafb_probe(struct de
vesafb_defined.left_margin = (vesafb_defined.xres / 8) & 0xf8;
vesafb_defined.hsync_len = (vesafb_defined.xres / 8) & 0xf8;
- if (vesafb_defined.bits_per_pixel > 8) {
- vesafb_defined.red.offset = screen_info.red_pos;
- vesafb_defined.red.length = screen_info.red_size;
- vesafb_defined.green.offset = screen_info.green_pos;
- vesafb_defined.green.length = screen_info.green_size;
- vesafb_defined.blue.offset = screen_info.blue_pos;
- vesafb_defined.blue.length = screen_info.blue_size;
- vesafb_defined.transp.offset = screen_info.rsvd_pos;
- vesafb_defined.transp.length = screen_info.rsvd_size;
- printk(KERN_INFO "vesafb: directcolor: "
- "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
- screen_info.rsvd_size,
- screen_info.red_size,
- screen_info.green_size,
- screen_info.blue_size,
- screen_info.rsvd_pos,
- screen_info.red_pos,
- screen_info.green_pos,
- screen_info.blue_pos);
- } else {
- vesafb_defined.red.length = 6;
- vesafb_defined.green.length = 6;
- vesafb_defined.blue.length = 6;
- }
+ vesafb_defined.red.offset = screen_info.red_pos;
+ vesafb_defined.red.length = screen_info.red_size;
+ vesafb_defined.green.offset = screen_info.green_pos;
+ vesafb_defined.green.length = screen_info.green_size;
+ vesafb_defined.blue.offset = screen_info.blue_pos;
+ vesafb_defined.blue.length = screen_info.blue_size;
+ vesafb_defined.transp.offset = screen_info.rsvd_pos;
+ vesafb_defined.transp.length = screen_info.rsvd_size;
+ printk(KERN_INFO "vesafb: %s: "
+ "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
+ (vesafb_defined.bits_per_pixel > 8) ?
+ "Truecolor" : "Pseudocolor",
+ screen_info.rsvd_size,
+ screen_info.red_size,
+ screen_info.green_size,
+ screen_info.blue_size,
+ screen_info.rsvd_pos,
+ screen_info.red_pos,
+ screen_info.green_pos,
+ screen_info.blue_pos);
vesafb_fix.ypanstep = ypan ? 1 : 0;
vesafb_fix.ywrapstep = (ypan>1) ? 1 : 0;
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2004-08-21 12:59 [PATCH 4/9][VESAFB]: Use 8-bit DAC for capable hardware Antonino A. Daplas
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