Re: [PATCH v3] drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 15 Feb 2017, Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
> On 14-02-17 17:12, Jani Nikula wrote:
>> From: Hans de Goede <hdegoede@redhat.com>
>>
>> If there is no OPREGION_ASLE_EXT then a VBT stored in mailbox #4 may
>> use the ASLE_EXT parts of the opregion. Adjust the vbt_size calculation
>> for a vbt in mailbox #4 for this.
>>
>> This fixes the driver not finding the VBT on a jumper ezpad mini3
>> cherrytrail tablet and on a ACER SW5_017 machine.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>>
>> ---
>>
>> Hans, I'm resending because for some reason our CI didn't pick this
>> up. Fixed a s/one/on/ typo in the comment while at it.
>
> Ok. Let me know if you need me to do anything to move this forward.

No, just sit back. Pushed to drm-intel-next-queued, thanks for the
patch.

BR,
Jani.

>
> Regards,
>
> Hans
>
>
>> ---
>>  drivers/gpu/drm/i915/intel_opregion.c | 13 ++++++++++++-
>>  1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
>> index f4429f67a4e3..4a862a358c70 100644
>> --- a/drivers/gpu/drm/i915/intel_opregion.c
>> +++ b/drivers/gpu/drm/i915/intel_opregion.c
>> @@ -982,7 +982,18 @@ int intel_opregion_setup(struct drm_i915_private *dev_priv)
>>  			opregion->vbt_size = vbt_size;
>>  		} else {
>>  			vbt = base + OPREGION_VBT_OFFSET;
>> -			vbt_size = OPREGION_ASLE_EXT_OFFSET - OPREGION_VBT_OFFSET;
>> +			/*
>> +			 * The VBT specification says that if the ASLE ext
>> +			 * mailbox is not used its area is reserved, but
>> +			 * on some CHT boards the VBT extends into the
>> +			 * ASLE ext area. Allow this even though it is
>> +			 * against the spec, so we do not end up rejecting
>> +			 * the VBT on those boards (and end up not finding the
>> +			 * LCD panel because of this).
>> +			 */
>> +			vbt_size = (mboxes & MBOX_ASLE_EXT) ?
>> +				OPREGION_ASLE_EXT_OFFSET : OPREGION_SIZE;
>> +			vbt_size -= OPREGION_VBT_OFFSET;
>>  			if (intel_bios_is_valid_vbt(vbt, vbt_size)) {
>>  				DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion (Mailbox #4)\n");
>>  				opregion->vbt = vbt;
>>

-- 
Jani Nikula, Intel Open Source Technology Center