git: 99870c70bac7 - main - loader: rewrite vidc_install_font

[Toomas Soome]

The branch main has been updated by tsoome:

URL: https://cgit.FreeBSD.org/src/commit/?id=99870c70bac7440bb2224d990a503d87c5488323

commit 99870c70bac7440bb2224d990a503d87c5488323
Author:     Toomas Soome <tsoome at FreeBSD.org>
AuthorDate: 2021-01-05 22:09:30 +0000
Commit:     Toomas Soome <tsoome at FreeBSD.org>
CommitDate: 2021-01-06 08:20:04 +0000

    loader: rewrite vidc_install_font
    
    Instead of trying to set reasonable register values, save significant
    register values, then prepare for font upload and then restore
    registers from saved data.
    
    This seems to fix text mode for most cases where text mode breakage
    was reported.
---
 stand/i386/libi386/vidconsole.c | 66 +++++++++++++++++++++--------------------
 1 file changed, 34 insertions(+), 32 deletions(-)

diff --git a/stand/i386/libi386/vidconsole.c b/stand/i386/libi386/vidconsole.c
index e373bc638ee4..3eff40588dfc 100644
--- a/stand/i386/libi386/vidconsole.c
+++ b/stand/i386/libi386/vidconsole.c
@@ -772,7 +772,7 @@ vga_cp437_to_uni(uint8_t c)
 static void
 vidc_install_font(void)
 {
-	static uint8_t fsreg[8] = {0x0, 0x30, 0x5, 0x35, 0xa, 0x3a, 0xf, 0x3f};
+	uint8_t reg[7];
 	const uint8_t *from;
 	uint8_t volatile *to;
 	uint16_t c;
@@ -788,34 +788,48 @@ vidc_install_font(void)
 		return;
 
 	/* Sync-reset the sequencer registers */
-	vga_set_seq(VGA_REG_BASE, 0x00, 0x01);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_RESET, VGA_SEQ_RST_NAR);
+
+	reg[0] = vga_get_seq(VGA_REG_BASE, VGA_SEQ_MAP_MASK);
+	reg[1] = vga_get_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE);
+	reg[2] = vga_get_seq(VGA_REG_BASE, VGA_SEQ_MEMORY_MODE);
+	reg[3] = vga_get_grc(VGA_REG_BASE, VGA_GC_READ_MAP_SELECT);
+	reg[4] = vga_get_grc(VGA_REG_BASE, VGA_GC_MODE);
+	reg[5] = vga_get_grc(VGA_REG_BASE, VGA_GC_MISCELLANEOUS);
+	reg[6] = vga_get_atr(VGA_REG_BASE, VGA_AC_MODE_CONTROL);
+
+	/* Screen off */
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE,
+	    reg[1] | VGA_SEQ_CM_SO);
+
 	/*
 	 * enable write to plane2, since fonts
 	 * could only be loaded into plane2
 	 */
-	vga_set_seq(VGA_REG_BASE, 0x02, 0x04);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_MAP_MASK, VGA_SEQ_MM_EM2);
 	/*
 	 * sequentially access data in the bit map being
 	 * selected by MapMask register (index 0x02)
 	 */
-	vga_set_seq(VGA_REG_BASE, 0x04, 0x07);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_MEMORY_MODE, 0x07);
 	/* Sync-reset ended, and allow the sequencer to operate */
-	vga_set_seq(VGA_REG_BASE, 0x00, 0x03);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_RESET,
+	    VGA_SEQ_RST_SR | VGA_SEQ_RST_NAR);
 
 	/*
 	 * select plane 2 on Read Mode 0
 	 */
-	vga_set_grc(VGA_REG_BASE, 0x04, 0x02);
+	vga_set_grc(VGA_REG_BASE, VGA_GC_READ_MAP_SELECT, 0x02);
 	/*
 	 * system addresses sequentially access data, follow
 	 * Memory Mode register bit 2 in the sequencer
 	 */
-	vga_set_grc(VGA_REG_BASE, 0x05, 0x00);
+	vga_set_grc(VGA_REG_BASE, VGA_GC_MODE, 0x00);
 	/*
 	 * set range of host memory addresses decoded by VGA
 	 * hardware -- A0000h-BFFFFh (128K region)
 	 */
-	vga_set_grc(VGA_REG_BASE, 0x06, 0x00);
+	vga_set_grc(VGA_REG_BASE, VGA_GC_MISCELLANEOUS, 0x00);
 
 	/*
 	 * This assumes 8x16 characters, which yield the traditional 80x25
@@ -833,35 +847,23 @@ vidc_install_font(void)
 			*to++ = *from++;
 	}
 
+	vga_set_atr(VGA_REG_BASE, VGA_AC_MODE_CONTROL, reg[6]);
+
 	/* Sync-reset the sequencer registers */
-	vga_set_seq(VGA_REG_BASE, 0x00, 0x01);
-	/* enable write to plane 0 and 1 */
-	vga_set_seq(VGA_REG_BASE, 0x02, 0x03);
-	/*
-	 * enable character map selection
-	 * and odd/even addressing
-	 */
-	vga_set_seq(VGA_REG_BASE, 0x04, 0x03);
-	/*
-	 * select font map
-	 */
-	vga_set_seq(VGA_REG_BASE, 0x03, fsreg[s]);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_RESET, VGA_SEQ_RST_NAR);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_MAP_MASK, reg[0]);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_MEMORY_MODE, reg[2]);
 	/* Sync-reset ended, and allow the sequencer to operate */
-	vga_set_seq(VGA_REG_BASE, 0x00, 0x03);
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_RESET,
+	    VGA_SEQ_RST_SR | VGA_SEQ_RST_NAR);
 
 	/* restore graphic registers */
+	vga_set_grc(VGA_REG_BASE, VGA_GC_READ_MAP_SELECT, reg[3]);
+	vga_set_grc(VGA_REG_BASE, VGA_GC_MODE, reg[4]);
+	vga_set_grc(VGA_REG_BASE, VGA_GC_MISCELLANEOUS, (reg[5] & 0x03) | 0x0c);
 
-	/* select plane 0 */
-	vga_set_grc(VGA_REG_BASE, 0x04, 0x00);
-	/* enable odd/even addressing mode */
-	vga_set_grc(VGA_REG_BASE, 0x05, 0x10);
-	/*
-	 * range of host memory addresses decoded by VGA
-	 * hardware -- B8000h-BFFFFh (32K region)
-	 */
-	vga_set_grc(VGA_REG_BASE, 0x06, 0x0e);
-	/* enable all color plane */
-	vga_set_atr(VGA_REG_BASE, 0x12, 0x0f);
+	/* Screen on */
+	vga_set_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE, reg[1] & 0xdf);
 }
 
 bool