From aa714d286f2ea5fae3ca8c75acd03d8694fb657e Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Wed, 4 Mar 2015 16:47:12 +0800 Subject: x86/PCI/ACPI: Relax ACPI resource descriptor checks to work around BIOS bugs Some BIOSes report incorrect length for ACPI address space descriptors, so relax the checks to avoid regressions. This issue has appeared several times as: 3162b6f0c5e1 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1") d558b483d5a7 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1") f238b414a74a ("PNPACPI: compute Address Space length rather than using _LEN") 48728e077480 ("x86/PCI: compute Address Space length rather than using _LEN") Please refer to https://bugzilla.kernel.org/show_bug.cgi?id=94221 for more details and example malformed ACPI resource descriptors. Link: https://bugzilla.kernel.org/show_bug.cgi?id=94221 Fixes: 593669c2ac0f (x86/PCI/ACPI: Use common ACPI resource interfaces ...) Signed-off-by: Jiang Liu Tested-by: Dave Airlie Tested-by: Prakash Punnoor Signed-off-by: Rafael J. Wysocki --- drivers/acpi/resource.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c index c723668e3e27..5589a6e2a023 100644 --- a/drivers/acpi/resource.c +++ b/drivers/acpi/resource.c @@ -42,8 +42,10 @@ static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io) * CHECKME: len might be required to check versus a minimum * length as well. 1 for io is fine, but for memory it does * not make any sense at all. + * Note: some BIOSes report incorrect length for ACPI address space + * descriptor, so remove check of 'reslen == len' to avoid regression. */ - if (len && reslen && reslen == len && start <= end) + if (len && reslen && start <= end) return true; pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n", -- cgit v1.2.3-70-g09d2 From 6e17cb12881ba8d5e456b89f072dc6b70048af36 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 1 Mar 2015 10:41:37 +0000 Subject: ACPI / video: Load the module even if ACPI is disabled 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 Signed-off-by: Chris Wilson Cc: Daniel Vetter Cc: Jani Nikula Cc: All applicable Acked-by: Aaron Lu [ rjw: Fixed up the new comment in acpi_video_init() ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/video.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/acpi') diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index debd30917010..5f98ac69729a 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -2176,6 +2176,17 @@ 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()) -- cgit v1.2.3-70-g09d2 From 28d634038d8fed8d25b92f21b728318a79c0be00 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 1 Mar 2015 10:41:38 +0000 Subject: ACPI / video: Propagate the error code for acpi_video_register Report the actual error code from acpi_bus_register_driver(), it may help future debugging (typically ENODEV as previously reported, but the unusual cases are where it may help most). Signed-off-by: Chris Wilson Acked-by: Aaron Lu Signed-off-by: Rafael J. Wysocki --- drivers/acpi/video.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 5f98ac69729a..26eb70c8f518 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -2110,7 +2110,8 @@ static int __init intel_opregion_present(void) int acpi_video_register(void) { - int result = 0; + int ret; + if (register_count) { /* * if the function of acpi_video_register is already called, @@ -2122,9 +2123,9 @@ int acpi_video_register(void) mutex_init(&video_list_lock); INIT_LIST_HEAD(&video_bus_head); - result = acpi_bus_register_driver(&acpi_video_bus); - if (result < 0) - return -ENODEV; + ret = acpi_bus_register_driver(&acpi_video_bus); + if (ret) + return ret; /* * When the acpi_video_bus is loaded successfully, increase -- cgit v1.2.3-70-g09d2