Re: [PATCH 1/3] drm/i915/opregion: fix version check

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

On Fri, 08 Feb 2019, Jani Nikula <jani.nikula@intel.com> wrote:
> On Fri, 08 Feb 2019, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
>> On Fri, Feb 08, 2019 at 05:57:53PM +0200, Ville Syrjälä wrote:
>>> On Fri, Feb 08, 2019 at 05:09:51PM +0200, Jani Nikula wrote:
>>> > On Fri, 08 Feb 2019, Jani Nikula <jani.nikula@intel.com> wrote:
>>> > > The u32 version field encodes major version in the high word. We've been
>>> > > checking for version >= 0.2.
>>> > >
>>> > > Add opregion version logging while at it.
>>> > >
>>> > > Fixes: 04ebaadb9f2d ("drm/i915/opregion: handle VBT sizes bigger than 6 KB")
>>> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>> > > Cc: Imre Deak <imre.deak@intel.com>
>>> > > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>>> > > ---
>>> > >  drivers/gpu/drm/i915/intel_opregion.c | 11 +++++++++--
>>> > >  1 file changed, 9 insertions(+), 2 deletions(-)
>>> > >
>>> > > diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
>>> > > index 30ae96c5c97c..7e4152d97c45 100644
>>> > > --- a/drivers/gpu/drm/i915/intel_opregion.c
>>> > > +++ b/drivers/gpu/drm/i915/intel_opregion.c
>>> > > @@ -46,6 +46,9 @@
>>> > >  #define OPREGION_ASLE_EXT_OFFSET	0x1C00
>>> > >  
>>> > >  #define OPREGION_SIGNATURE "IntelGraphicsMem"
>>> > > +
>>> > > +#define OPREGION_VERSION(major, minor) (((major) << 16) | (minor))
>>> > > +
>>> > >  #define MBOX_ACPI      (1<<0)
>>> > >  #define MBOX_SWSCI     (1<<1)
>>> > >  #define MBOX_ASLE      (1<<2)
>>> > > @@ -924,6 +927,10 @@ int intel_opregion_setup(struct drm_i915_private *dev_priv)
>>> > >  	opregion->header = base;
>>> > >  	opregion->lid_state = base + ACPI_CLID;
>>> > >  
>>> > > +	DRM_DEBUG_DRIVER("ACPI OpRegion version %u.%u\n",
>>> > > +			 opregion->header->opregion_ver >> 16,
>>> > > +			 opregion->header->opregion_ver & 0xffff);
>>> > > +
>>> > 
>>> > This is ridiculous and maddening. On our CI APL this prints [1]:
>>> > 
>>> > <7>[    7.029368] [drm:intel_opregion_setup [i915]] ACPI OpRegion version 512.0
>>> > 
>>> > Yes, version 512.0.
>>> > 
>>> > Digging into it, I found one random version of the opregion spec that
>>> > has:
>>> > 
>>> > 	Bits [31:16] - Major Version Number
>>> > 	Bits [23:0] - Minor Version Number
>>> > 
>>> > The minor is supposed to be [15:0]. But this APL (maybe others, need to
>>> > investigate) has the major version encoded to bits 31:24.
>>> 
>>> Most copies of the spec I have seem to have the 24 + 16 bits mess.
>>> 
>>> They also claim that HSW+ should generally have version 3.0. So
>>> not sure this 2.0 vs. 2.1 business even makes sense.
>>> 
>>> We should probably grab the opregion from all the machines we have
>>> around and see what they actully look like.
>>
>> Here's the output from my random opregion collection:
>> bsw_rvp_BRAS.opregion
>> 	over:	0x02000000
>> bw_ASUS_P5E-VM_HDMI.opregion
>> 	over:	0x01010000
>> cl_hp_compaq_6910p.opregion
>> 	over:	0x01010000
>
> So judging by the multitude of specs and interpretations, these two
> could be a lot of things.
>
> v101.0		16+16 BCD
> v257.0		16+16
> v1.10000	8+24 BCD
> v1.65536	8+24
>
> However it feels more likely all of these are really 8 bits major + 8
> bits minor (BCD or not) + 16 bits reserved/zero, i.e.
>
> v1.1
>
> But that interpretation isn't supported by *any* of the specs I have.

Turns out that's what all the other software thinks, undocumented.

31:24 major
23:16 minor
15:8  revision
7:0   reserved

No idea about BCD...

BR,
Jani.


>
> BR,
> Jani.
>
>
>> ctg_dell_latitude_e5400.opregion
>> 	over:	0x02000000
>> dell_xps_13_9350.opregion
>> 	over:	0x02000000
>> elk.opregion
>> 	over:	0x02000000
>> hsw_brix_pro_GIGABYTE_M4HM87P.opregion
>> 	over:	0x02000000
>> hsw_Gigabyte_Z97x-UD5H.opregion
>> 	over:	0x02000000
>> hsw_shark_bay_HSWLPTU1.opregion
>> 	over:	0x02000000
>> ilk_dell_latiture_e5410.opregion
>> 	over:	0x02000000
>> ivb_BHZ7710H.opregion
>> 	over:	0x02000000
>> ivb_Lenovo_ThinkPad_X1_Carbon.opregion
>> 	over:	0x02000000
>> skl_MSI_MS-7971.opregion
>> 	over:	0x02000000
>> snb_Dell_XPS_8300.opregion
>> 	over:	0x02000000
>> vlv_ffrd8_BLAKFF81.ppregion
>>
>> So looks like all of them have the major in [31:24].

-- 
Jani Nikula, Intel Open Source Graphics Center
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