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

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

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.

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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