[GTALUG] Coffee Lake GPU support [was: IBM Mainframe and z/OS]

[Russell]

On December 9, 2017 1:58:58 PM EST, "D. Hugh Redelmeier via talk" <talk at gtalug.org> wrote:
>| From: Russell via talk <talk at gtalug.org>
>
>| On December 9, 2017 9:02:03 AM EST, "Stewart C. Russell via talk"
><talk at gtalug.org> wrote:
>
>| > http://www.masswerk.at/misc/card-punch-typography/
>| 
>| Very interesting link. Also nice to know how little endian transport 
>| "return zero" errors we're being handled back in the day.
>
>Return zero?

Sorry, a bit of a joke about transliterative errors.

Wasn't the TLS heartbeat issue, in essence, a return zero error. The return handler expected "0" but got "" null and granted access as a permissive failover. 

>
>| Most recently, after trying several kernel taints
>
>What does that mean?  As far as I
 understand, the kernel reports
>itself tainted if it observes any of a number of distateful things.
>Like loading proprietary kernel modules.  The idea is that kernel
>maintainers will ignore problem reports from folks running such
>modules.

I tried some recommendations, adding  i915.alpha_support=1 and a few others on boot. I was eventually able to change display resolutions, but this triggered a kernel crash. The system recovered but I didn't even see the ABRT report until I updated F27. 

Now I'm at 4.13.16-302.fc27.x86_64. running Nvidia using their own driver. I've tainted the kernel by blacklisting Nouveau, which in fact appears to have provided me with more resolution choices. I may revert soon. 

I chose F27 for this build because I was very impressed with Gnome on Wayland on my HP-110. It handles display much better than Mint or Bunsen etc on it.

>
>| on my Intel gpu, which 
>| is having font rendering issues, I dumped my DSDT table and found 
>| namespace/pstate conflicts in returning zero as serialized data.
>
>I'm not sure what "returning zero as serialized data" means in this
>context. 
>
>There are lots of buggy ACPI tables.  If you are lucky, you can ignore
>them.
>
>You can disassemble ACPI tables and recompile them and get a surprising
>number of compiler warnings.  I vaguely remember hearing the firmware
>developers generally use a Microsoft ACPI compiler but we Linux users
>use an Intel compiler, and it flags more errors (or at least different
>errors) than the Microsoft one.
>
>One of the common errors is ACPI routines falling off the end rather
>than returning a value.
>
>Does ACPI have anything to say about GPUs?

Not specifically, there are method, object and value references, which I'm currently trying to get an understanding of. Keeping pstate values stable and ordered, for finer grained control over reporting power management, seems to conflict with some methods.

This warning, which looks to me like it's saying I'm getting 1 when I expect 0, is related to one ACPI error repeated seven times.

This is where my base math skills fall down. Warning 4089. Is it a 0 object or a zero method?

Line 4093 =length appears to exceed line 4091 =range maximum

dsdt.dsl    180:     Name (IOHB, 0x0290)
Warning  4089 -              ^ Object is not referenced

4088                 DWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed, NonCacheable, ReadWrite,

  4089                     0x00000000,         // Granularity

  4090                     0x00000000,         // Range Minimum

  4091                     0xDFFFFFFF,         // Range Maximum

  4092                     0x00000000,         // Translation Offset

  4093                     0xE0000000,         // Length

THE ERROR is 6074

dsdt.dsl  19786:     Method (TBTD, 1, Serialized)

Error    6074 -                ^ Name already exists in scope (TBTD)

   Original name creation/declaration below: 

   dsdt.dsl    164:     External (TBTD, MethodObj)    // 1 Arguments

dsdt.dsl  19858:     Method (TBTF, 1, Serialized)

Error    6074 -                ^ Name already exists in scope (TBTF)

   Original name creation/declaration below: 

   dsdt.dsl    165:     External (TBTF, MethodObj)    // 1 Arguments

dsdt.dsl  19979:     Method (MMRP, 1, Serialized)

Error    6074 -                ^ Name already exists in scope (MMRP)

   Original name creation/declaration below: 

   dsdt.dsl    124:     External (MMRP, MethodObj)    // 1 Arguments

dsdt.dsl  19987:     Method (MMTB, 1, Serialized)

Error    6074 -                ^ Name already exists in scope (MMTB)

   Original name creation/declaration below: 

   dsdt.dsl    125:     External (MMTB, MethodObj)    // 1 Arguments

dsdt.dsl  20009:     Method (FFTB, 1, Serialized)

Error    6074 -                ^ Name already exists in scope (FFTB)

   Original name creation/declaration below: 

   dsdt.dsl    113:     External (FFTB, MethodObj)    // 1 Arguments

>
>| Seven 
>| errors and a couple of hundred warnings. I tried Rawhide for better
>gpu 
>| drivers but no joy there.
>
>Perhaps you need this kernel boot parameter:
>	i915.alpha_support=1
>Your kernel probably needs to be 4.13 or newer.
>
>See
><https://www.phoronix.com/scan.php?page=article&item=coffee-uhd-graphics&num=1>
>
>(I speak with no experience.)

I speak with many uneducated guesses as I try to stitch hardware together. 

When I was first overclocking, jumper by jumper, it struck me as odd that changing just a couple of jumpers on the motherboard could so drastically improve performance. 

On the other hand, getting a breakout lcd to report the clock speed changes accurately, required 42 jumpers to be precisely set or it wouldn't  display data at all. 

If it isn't the trees, it's the forest. I sort of treat this mail list a little like a machete; it helps to cut away some of the undergrowth and keep stuff in perspective.

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-- 
Russell