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Re: [PATCH] Fix infinite loop in grub_pit_wait()
From: |
Marco Gerards |
Subject: |
Re: [PATCH] Fix infinite loop in grub_pit_wait() |
Date: |
Thu, 07 Aug 2008 18:26:34 +0200 |
User-agent: |
Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) |
Christian Franke <address@hidden> writes:
> 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 <address@hidden>
>
> * 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.
Small nitpick: use a double space
> 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);
These lines are too long, please break them properly.
--
Marco