From: Clemens Ladisch <clemens@ladisch.de>
To: linux-kernel@vger.kernel.org
Cc: akpm@osdl.org, Bob Picco <bob.picco@hp.com>,
Clemens Ladisch <clemens@ladisch.de>
Subject: [PATCH 6/7] HPET-RTC: fix timer config register accesses
Date: Wed, 28 Sep 2005 09:12:31 +0200 (MEST) [thread overview]
Message-ID: <20050928071231.23025.2922.balrog@turing> (raw)
In-Reply-To: <20050928071155.23025.43523.balrog@turing>
Make sure that the RTC timer is in non-periodic mode; some stupid BIOS
might have initialized it to periodic mode.
Furthermore, don't set the SETVAL bit in the config register. This
wouldn't have any effect unless the timer was in period mode (which it
isn't), and then the actual timer frequency would be half that of the
desired one because incrementing the comparator in the interrupt
handler would be done after the hardware has already incremented it
itself.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Index: linux-2.6.13/arch/i386/kernel/time_hpet.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/time_hpet.c 2005-09-27 21:56:38.000000000 +0200
+++ linux-2.6.13/arch/i386/kernel/time_hpet.c 2005-09-27 21:59:13.000000000 +0200
@@ -309,7 +309,8 @@ int hpet_rtc_timer_init(void)
local_irq_restore(flags);
cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
+ cfg &= ~HPET_TN_PERIODIC;
+ cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_writel(cfg, HPET_T1_CFG);
return 1;
@@ -335,12 +336,6 @@ static void hpet_rtc_timer_reinit(void)
cnt = hpet_readl(HPET_T1_CMP);
cnt += hpet_tick*HZ/hpet_rtc_int_freq;
hpet_writel(cnt, HPET_T1_CMP);
-
- cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
- hpet_writel(cfg, HPET_T1_CFG);
-
- return;
}
/*
Index: linux-2.6.13/arch/x86_64/kernel/time.c
===================================================================
--- linux-2.6.13.orig/arch/x86_64/kernel/time.c 2005-09-27 21:57:27.000000000 +0200
+++ linux-2.6.13/arch/x86_64/kernel/time.c 2005-09-27 21:59:13.000000000 +0200
@@ -1139,7 +1139,8 @@ int hpet_rtc_timer_init(void)
local_irq_restore(flags);
cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
+ cfg &= ~HPET_TN_PERIODIC;
+ cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_writel(cfg, HPET_T1_CFG);
return 1;
@@ -1165,12 +1166,6 @@ static void hpet_rtc_timer_reinit(void)
cnt = hpet_readl(HPET_T1_CMP);
cnt += hpet_tick*HZ/hpet_rtc_int_freq;
hpet_writel(cnt, HPET_T1_CMP);
-
- cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
- hpet_writel(cfg, HPET_T1_CFG);
-
- return;
}
/*
next prev parent reply other threads:[~2005-09-28 7:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-28 7:11 [PATCH 0/7] HPET fixes and enhancements Clemens Ladisch
2005-09-28 7:12 ` [PATCH 1/7] HPET: remove unused variable Clemens Ladisch
2005-09-28 7:12 ` [PATCH 2/7] HPET: remove superfluous register reads Clemens Ladisch
2005-09-28 7:12 ` [PATCH 3/7] HPET: allow non-power-of-two frequencies Clemens Ladisch
2005-09-28 7:12 ` [PATCH 4/7] HPET: allow shared interrupts Clemens Ladisch
2005-09-28 7:12 ` [PATCH 5/7] HPET-RTC: disable interrupt when no longer needed Clemens Ladisch
2005-09-28 13:03 ` Venkatesh Pallipadi
2005-09-29 6:30 ` Clemens Ladisch
2005-09-28 7:12 ` Clemens Ladisch [this message]
2005-09-28 13:06 ` [PATCH 6/7] HPET-RTC: fix timer config register accesses Venkatesh Pallipadi
2005-09-28 7:12 ` [PATCH 7/7] HPET-RTC: cache the comparator register Clemens Ladisch
2005-09-28 15:44 ` [PATCH 0/7] HPET fixes and enhancements Bob Picco
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