linux-kernel - Re: [bisected] PS/2 keyboard and mouse dead on resume on Intel D845BG

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Date:	Sun, 7 Oct 2012 21:00:09 +0200
From:	Ondrej Zary <linux@...nbow-software.org>
To:	Matthew Garrett <mjg@...hat.com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, Len Brown <len.brown@...el.com>,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [bisected] PS/2 keyboard and mouse dead on resume on Intel D845BG

On Sunday 07 October 2012 15:13:27 Ondrej Zary wrote:
> Hello,
> Intel D845BG board comes out of S3 with PS/2 keyboard and mouse completely
> dead. The machine works otherwise (with USB keyboard or over network). When
> rebooted in this state, the BIOS hangs with blank screen. I have the latest
> BIOS installed (P08).
>
> Old kernels worked. Bisection pointed to commit:
> b6dacf63e9fb2e7a1369843d6cef332f76fca6a3
> (ACPI: Unconditionally set SCI_EN on resume)
>
> Commenting out this line in drivers/acpi/sleep.c:
> 	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
> fixes the problem.
>
> Any ideas why this breaks on this system?

Added acpi_read_bit_register there and it seems that SCI_EN is already set!

This patch fixes the problem here. I wonder how this affects systems that
require SCI_EN to be set.

--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -271,6 +271,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	acpi_status status = AE_OK;
 	u32 acpi_state = acpi_target_sleep_state;
 	int error;
+	u32 sci_enabled;
 
 	ACPI_FLUSH_CPU_CACHE();
 
@@ -289,7 +290,9 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	}
 
 	/* This violates the spec but is required for bug compatibility. */
-	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
+	acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &sci_enabled);
+	if (!sci_enabled)
+		acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
 
 	/* Reprogram control registers */
 	acpi_leave_sleep_state_prep(acpi_state);

-- 
Ondrej Zary
--
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