52 lines
2.0 KiB
Diff
52 lines
2.0 KiB
Diff
commit 7ba0dea4158155a68b833982199691dbc2d4e6dc
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Author: Matthew Garrett <mjg@redhat.com>
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Date: Mon Apr 19 16:51:39 2010 -0400
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acpi: Fall back to manually changing SCI_EN
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The ACPI spec tells us that the ACPI SCI_EN bit is under hardware control
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and shouldn't be touched by the OS. It seems that the Leading Other OS
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ignores this and some machines expect this behaviour. We have a blacklist
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for these, but given that we're able to detect the failure case and the
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alternative to breaking the spec is letting the machine crash and burn,
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let's try falling back when we know the alternative is a mostly-dead
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machine.
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Signed-off-by: Matthew Garrett <mjg@redhat.com>
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diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
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index f74834a..79df8d4 100644
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--- a/drivers/acpi/sleep.c
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+++ b/drivers/acpi/sleep.c
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@@ -227,6 +227,7 @@ static int acpi_suspend_begin(suspend_state_t pm_state)
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static int acpi_suspend_enter(suspend_state_t pm_state)
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{
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acpi_status status = AE_OK;
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+ acpi_status enable_status = AE_OK;
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unsigned long flags = 0;
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u32 acpi_state = acpi_target_sleep_state;
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@@ -254,10 +255,19 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
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}
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/* If ACPI is not enabled by the BIOS, we need to enable it here. */
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- if (set_sci_en_on_resume)
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+ if (!set_sci_en_on_resume)
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+ enable_status = acpi_enable();
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+
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+ if (set_sci_en_on_resume || enable_status == AE_NO_HARDWARE_RESPONSE)
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+ /* If we're still in legacy mode then we have a problem. The
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+ * spec tells us that this bit is under hardware control, but
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+ * there's no plausible way that the OS can transition back to
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+ * legacy mode so our choices here are to either ignore the
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+ * spec or crash and burn horribly. The latter doesn't seem
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+ * like it's ever going to be the preferable choice, so let's
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+ * live dangerously.
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+ */
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acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
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- else
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- acpi_enable();
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/* Reprogram control registers and execute _BFS */
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acpi_leave_sleep_state_prep(acpi_state);
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