From: Clemens Ladisch Date: Sun, 30 Oct 2005 23:03:36 +0000 (-0800) Subject: [PATCH] hpet-RTC: fix timer config register accesses X-Git-Tag: v2.6.15-rc1~59^2~15^2~21 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5f819949ee4e5a06c2e0054cbb42f3f0d170d779;p=linux-2.6 [PATCH] hpet-RTC: fix timer config register accesses 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 Acked-by: Venkatesh Pallipadi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c index 23e81fcbea..cb1f313858 100644 --- a/arch/i386/kernel/time_hpet.c +++ b/arch/i386/kernel/time_hpet.c @@ -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; } /* diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 7037ca668c..35a896ef4c 100644 --- a/arch/x86_64/kernel/time.c +++ b/arch/x86_64/kernel/time.c @@ -1128,7 +1128,8 @@ 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; @@ -1154,12 +1155,6 @@ 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; } /*