On Mon, 29 Aug 2022 17:19:16 +1000
Jonathan Gray <j...@jsg.id.au> wrote:
> On Mon, Aug 29, 2022 at 07:56:40AM +0100, Hashim Mahmoud wrote:
> > This iMac's screen works fine, but always turns off when the radeon
> > GPU driver is loaded on any UNIX (tried Linux Mint and NomadBSD as
> > well). I had to install OpenBSD on another machine since I was
> > installing to an SD card, as I didn't have any (big enough) spare
> > SSDs or USBs, and writing to the SD card from the installer on the
> > same iMac gives me permission errors.
> >
> > I had installed the radeon firmware already by the time I put the SD
> > card into the iMac. The GPU seems to work fine and I can login and
> > run commands blindly, but the display is off... until I had the
> > bright idea to connect a display over the DisplayPort at boot time,
> > via a VGA to mini DisplayPort adapter. The internal eDP display
> > worked, but the tty framebuffer took the resolution of the external
> > display (similar to what would happen when a low resolution laptop
> > is connected to a higher resolution display, and both displays are
> > on), which is 1440x900, and the external display receives no
> > output, though Xorg seems to acknowledge its existence and renders
> > itself as if that display exists, as the xenodm login window is not
> > available on the main display, and the mouse disappears as if it
> > went to another display when hitting the left edge. I can login
> > blind and run `xrandr --output DisplayPort-0 --off`, and everything
> > seems to work perfectly fine and GPU accelerated, as the output of
> > `glxinfo -B` indicates, and glxgears runs smoothly.
> >
> > However, this only works if the DisplayPort is connected at boot
> > time:
> >
> > - If it is disconnected after the radeon driver is loaded, but X
> > hasn't started yet, then the display goes black again, but I can
> > plug it back in and the display shows up as normal (still in
> > 1440x900, though), and I get this in blue: `[drm] *ERROR* chosen
> > encoder in use 0`. No idea what that means.
> >
> > - Once X is started however, I can just disconnect the DisplayPort,
> > and life is good :) ... except I get the following in xconsole:
> > ```
> > [drm] *ERROR* displayport link status failed
> > [drm] *ERROR* clock recovery failed
> > [drm] *ERROR* displayport link status failed
> > [drm] *ERROR* clock recovery failed
> > ```
> > - Doesn't seem to effect me in any way, though.
> >
> > - I also get this error message, when I switch from my X session to
> > tty: `[drm] *ERROR*
> > rv770_restrict_performance_levels_before_switch failed`. Also seems
> > to have no effect.
> > - Note that these errors only appear in xconsole and not on the
> > actual console in blue... weird.
> >
> >
> > Is there some sort of software remedy for this? I doubt this (unless
> > someone can tell me otherwise), so I was thinking of getting
> > something like a Raspberry Pi Zero or an Arduino, and connecting to
> > the DisplayPort, making it like some sort of dummy DisplayPort
> > input by programming it... I'm not sure at all how to go about
> > doing this, as I'm a very amateur programmer, but I know that it
> > *should* be theoretically possible; any pointers would be very
> > appreciated.
>
> Does this help?
>
> RV730 has DCE3.2
>
> Index: sys/dev/pci/drm/radeon/atombios_encoders.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/drm/radeon/atombios_encoders.c,v
> retrieving revision 1.17
> diff -u -p -U6 -r1.17 atombios_encoders.c
> --- sys/dev/pci/drm/radeon/atombios_encoders.c 24 Feb 2022
> 12:49:47 -0000 1.17 +++
> sys/dev/pci/drm/radeon/atombios_encoders.c 29 Aug 2022
> 07:12:12 -0000 @@ -2189,13 +2189,14 @@ int
> radeon_atom_pick_dig_encoder(struct /*
> * On DCE32 any encoder can drive any block so usually just
> use crtc id,
> * but Apple thinks different at least on iMac10,1, so there
> use linkb,
> * otherwise the internal eDP panel will stay dark.
> */
> if (ASIC_IS_DCE32(rdev)) {
> - if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1"))
> + if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1") ||
> + dmi_match(DMI_PRODUCT_NAME, "iMac11,2"))
> enc_idx = (dig->linkb) ? 1 : 0;
> else
> enc_idx = radeon_crtc->crtc_id;
>
> goto assigned;
> }
Sorry for the relatively late reply, this is my first time compiling
the kernel from source... but man you're a life saver; it worked! I do
get this error though:
`WARNING bo->pin_count failed at /usr/src/sys/dev/pci/drm/ttm/ttm_bo.c:409`
Which also doesn't affect me, but worth pointing out. I tried making an
external monitor work over the DisplayPort, but seems to still have the
problem of rendering but not actually outputting... I might've got the
above error after I tried making the monitor work, I'm not sure, but
not like it matters much; no external monitor isn't a deal breaker for
me, but if there's a fix I'd gladly accept it.
Is there a way to fix this on Linux or FreeBSD? iirc all the UNIXes
share the same GPU drivers, so surely there's a fix. Thanks a lot, man.
