On 2020-01-02 00:26 +0000, Ken Moffat via blfs-dev wrote:
> Apologies for breaking the thread, I thought I had _copied_
> Pierre's mail to my notes, and then I edited my note on microcode
> to include the TLAs for Broadwell etc so that I could understand the
> intel release notes next time, and deleted the copy.  But what I'd
> actually done was Save the mail, so I'm now posting the original
> from the archive.  Sorry about that, blame it on too much
> williewaught [1.]
> 
> And thanks for finding these explanations of the TLAs.
> 
> Pierre wrote:
> 
> > Hi,
> > 
> > While investigating the bug in libva-2.6.0, I realized that there was a new
> > vaapi driver for intel GEN8+ graphics: iHD_drv_video.so
> > 
> > The source is at https://github.com/intel/media-driver.
> > 
> > If anybody with the appropriate hardware wants to try...
> > Personally, I am at 4th gen intel (Haswell), so I cannot test.
> > Note that it also requires the gmmlib graphics memory management library:
> > https://github.com/intel/gmmlib.
> > 
> > Note that libva-2.6.0 has a bug (https://github.com/intel/libva/issues/355)
> > which prevents using the i965 driver if the iHD driver is also installed. I
> > have provided a patch to fix this issue
> > (https://github.com/intel/libva/issues/356), but I cannot test for lack of
> > hardware! So if anybody has a recent intel CPU (
> >     BDW (Broadwell)
> >     SKL (Skylake)
> >     BXT (Broxton) / APL (Apollo Lake)
> >     KBLx (KBL/Kaby Lake; CFL/Coffe Lake; WHL/Whiskey Lake; CML/Comet Lake;
> > AML/Amber Lake)
> >     ICL (Ice Lake)
> >     JSL (Jasper Lake)/EHL (Elkhart Lake)
> >     TGL (Tiger Lake)
> > )
> > please try it, thanks

I have a new Core i7-1065G7 laptop.  The legacy libva-intel-driver just doesn't
work on Gen 11 graphic so I tried the new iHD driver.

Gstreamer refuses to use iHD driver with libva (by default it only utilizes
libva-intel-driver).  I tried to force Gstreamer to use iHD.  It works with
"gst-play-1.0" but breaks video replay in WebKitGTK (I tried 1080p videos on
YouTube and Bilibili).  So finally I had to build intel-media-sdk and gst-msdk
plugin (in gst-plugins-bad) to use the Gen 11 iGPU to accelerate video replay.

> I _do_ have a low-end skylake (i3 6100), but I don't think I'll have
> time to look at this in January, and probably not in February.  But
> nevertheless, some comments.
> 
> First, GEN8+ is not the same as 8nnn CPUs (Kaby Lake etc).
> Broadwell is 5nnn, Skylake are 6nnn (or 7nnn for some, but maybe
> those lack integrated graphics).  I think it means the 8th and later
> generations of intel integrated graphics.
> 
> Oddly, the link to the media-driver looks correct, but 404s when I
> click on it from the archive.  But looking at the README there are
> two types of build: Full Feature and Free Kernel.  I don't grok the
> explanation of the differences, but I see that Arch have a build
> which looks straightforward, ditto intel-gmmlib.
> 
> Importantly, HuC firmware is needed for several of the encoders,
> this is currently disabled by default in released kernels (I believe
> there is an attempt to get it enabled by default in 5.5 or perhaps
> 5.6).  The kernel docs apparently explain how to enable it on
> current kernels, but I would be very wary of doing that until it
> arrives in a released kernel, because there have been so many
> problems.  Back in July phoronix reported it would be loaded by
> default in IceLake (Gen 11).  In particular,
> https://wiki.archlinux.org/index.php/Intel_graphics#Enable_GuC_/_HuC_firmware_loading
> says that loading GuC/HuC firmware can cause freezing, e.g. when
> resuming from hibernation.  But the bottom of that page says it is
> out of date: Reason: GuC submission has been completely disabled in
> the kernel, due to it reducing performance and causing bugs. Setting
> enable_guc=3 has no effect.
> 
> Yes, that is GuC not HuC, but it doesn't give me a lot of
> confidence.  Once a release kernel enables HuC on 5nnn and 6nnn CPUs
> with integrated graphics, things ought to be fine.  But meanwhile, I
> would class it as "here might be dragons".
> 
> Hmm, found the phoronix article I was thinking of,
> https://www.phoronix.com/scan.php?page=news_item&px=Intel-GuC-HuC-Auto-Enable-Again
> With a link to the patch.  On this AMD machine I've got kernel 5.4.5
> source, the patch has NOT been applied there:
> 
> > diff --git a/drivers/gpu/drm/i915/i915_params.h  
> > > b/drivers/gpu/drm/i915/i915_params.h
> > > index d29ade3b7de6..5736c55694fe 100644
> > > --- a/drivers/gpu/drm/i915/i915_params.h
> > > +++ b/drivers/gpu/drm/i915/i915_params.h
> > > @@ -54,7 +54,7 @@ struct drm_printer;
> > >         param(int, disable_power_well, -1) \
> > >         param(int, enable_ips, 1) \
> > >         param(int, invert_brightness, 0) \
> > > -       param(int, enable_guc, 0) \
> > > +       param(int, enable_guc, -1) \
> > >         param(int, guc_log_level, -1) \
> > >         param(char *, guc_firmware_path, NULL) \
> > >         param(char *, huc_firmware_path, NULL) \
> 
> (also a comment that GuC is only used for HuC authentication).
> 
> I've also got 5.5-rc4 source, and again this has NOT been applied.

My kernels (one from Arch and one built by myself) don't try to load GuC/HuC
firmwares.  /sys/kernel/debug says my iGPU doesn't need HuC, and GuC is
disabled.

> ĸen
> 
> 1. https://www.dsl.ac.uk/entry/snd/williewaught
> -- 
> The Laird o’Phelps spent Hogmanay declaring he was sober,
> Counted his feet to prove the fact and found he had one foot over.
>                           -- Louis MacNeice, Bagpipe Music
-- 
Xi Ruoyao <[email protected]>
School of Aerospace Science and Technology, Xidian University

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