Re: [9front] igfx on haswell

[qwx@sciops.net]

On Sat Nov 13 22:51:48 +0100 2021, krwmilz@gmail.com wrote:
> On Sat, Nov 13, 2021 at 10:42:17AM +0100, qwx@sciops.net wrote:
> > Great, thanks!  For hdmi/dvi to work, igfx must manage to get
> > an edid from the monitor, this doesn't happen with some of
> > them, but you might coerce it to work with yet another vgadb
> > entry for it, specifying a port with display=.  It will be on
> > one of the 4 remaining DP ports, 4-7 (3 is eDP).  There's no
> > way to force hdmi on a specific port though iirc.
> 
> i played around with aux/vga -pvV and it manages to get an edid
> for the internal display about 1/10 of the time. the other 9/10
> times the 8 edid header bytes contain random garbage. i tried
> comparing i915 drm code with igfx.c to find out why but no luck.
> 
> i have not tried getting the edid from an external display but
> suspect something similar is happening.

Interesting.  I'll play around with the x240 and retest with my
desktop, I've never had issues with that one with the monitors
I've used.  Reading the linux code isn't super helpful though,
it's just a huge mishmash of incomprehensible and undocumented
black magic.


> > If possible, please add the pci did to
> > /sys/src/9/pc/vgaigfx.c:152.  The hardware cursor should be
> > enabled when you invoke aux/vga.  If it's visible while
> > /dev/vgactl shows `hwgc igfxhwgc', it works.
> 
> i tried that, but got the same output as before. forcing it with
> 
> 	% echo hwgc igfxhwgc >/dev/vgactl
> 
> causes the cursor to disappear.

If you got the same output as before, it might be because you
haven't updated or installed a new kernel.  Your vgadb diff
shows that you had inserted the did in the correct ctrl
section which sets igfxhwgc, so that should happen
automatically when you boot with whatever params or use
aux/vga, ie. you shouldn't need to write to /dev/vgactl.  Not
to say that a bug isn't possible of course!


> > One last thing, could you please also say if:
> > 
> > 	; ls '#g'
> 
> prints nothing.

Great!

Thanks a lot, I'll push your diff and vgaigfx.c change,
and please report back about the cursor when possible.
I think we may now claim that we support broadwell!

Cheers,
qwx