i915.ko depends upon the acpi/video.ko module and so refuses to load if
ACPI is disabled at runtime if for example the BIOS is broken beyond
repair. acpi/video provides an optional service for i915.ko and so we
should just allow the modules to load, but do no nothing in order to let
the machines boot correctly.
Reported-by: Bill Augur <bill-auger@xxxxxxxxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/acpi/video.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index debd30917010..3b76aef79a1c 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -2176,6 +2176,16 @@ EXPORT_SYMBOL(acpi_video_unregister_backlight);
static int __init acpi_video_init(void)
{
+ /* Let the module load even if ACPI is disabled (e.g. due to
+ * a broken BIOS) so that i915.ko can still be loaded on such
+ * old systems without an AcpiOpRegion.
+ *
+ * acpi_video_register() will report -ENODEV later as well due
+ * to acpi_disabled when i915.ko tries to register itself afterwards.
+ */
+ if (acpi_disabled)
+ return 0;
+
dmi_check_system(video_dmi_table);
if (intel_opregion_present())
--
2.1.4
--
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