grub2 from current SVN hangs if run in VirtualPC, the problem was
introduced with 'svn diff -r 1779:1780'.
Here is a proposed fix.
Christian
2008-08-07 Christian Franke <[EMAIL PROTECTED]>
* kern/i386/pit.c (TIMER2_SPEAKER): New define.
(TIMER2_GATE): Likewise.
(grub_pit_wait): Add enable/disable of the timer2 gate
bit of port 0x61. This fixes a possible infinite loop.
diff --git a/kern/i386/pit.c b/kern/i386/pit.c
index d0a6eda..a3fab26 100644
--- a/kern/i386/pit.c
+++ b/kern/i386/pit.c
@@ -28,13 +28,26 @@
#define TIMER_ENABLE_LSB 0x20
#define TIMER_ENABLE_MSB 0x10
#define TIMER2_LATCH 0x20
+#define TIMER2_SPEAKER 0x02
+#define TIMER2_GATE 0x01
void
grub_pit_wait (grub_uint16_t tics)
{
+ /* Disable timer2 gate and speaker. */
+ grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE), TIMER2_REG_LATCH);
+
+ /* Set tics. */
grub_outb (TIMER2_SELECT | TIMER_ENABLE_LSB | TIMER_ENABLE_MSB, TIMER_REG_COMMAND);
grub_outb (tics & 0xff, TIMER2_REG_CONTROL);
grub_outb (tics >> 8, TIMER2_REG_CONTROL);
+ /* Enable timer2 gate, keep speaker disabled. */
+ grub_outb ((grub_inb (TIMER2_REG_LATCH) & ~ TIMER2_SPEAKER) | TIMER2_GATE, TIMER2_REG_LATCH);
+
+ /* Wait. */
while ((grub_inb (TIMER2_REG_LATCH) & TIMER2_LATCH) == 0x00);
+
+ /* Disable timer2 gate and speaker. */
+ grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE), TIMER2_REG_LATCH);
}
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