[PATCH 3.4 070/172] ACPI / video: Load the module even if ACPI is disabled

lizf
2015-06-16T09:23:16Z

From: Chris Wilson <chris@chris-wilson.co.uk>

3.4.108-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 6e17cb12881ba8d5e456b89f072dc6b70048af36 upstream.

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@programmer.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
Acked-by: Aaron Lu <aaron.lu@intel.com>
[ rjw: Fixed up the new comment in acpi_video_init() ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/acpi/video.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 8c5ad89..89cff37 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -1872,6 +1872,17 @@ EXPORT_SYMBOL(acpi_video_unregister);

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())
--
1.9.1