[BRLTTY] ‘empty console’

[Sebastian Humenda]

Hi Nicolas

sorry for the late reply.

Nicolas Pitre schrieb am Sun, Nov 17, 2019 at 02:09:52PM -0500:
> On Sun, 17 Nov 2019, Sebastian Humenda wrote:
> > Sebastian Humenda schrieb am 05.11.2019, 22:01 +0100:
> > >on a freshly installed GNU/Linux system I am experiencing an ‚empty’ screen with BRLTTY.
> > >After booting the machine, the braille display is empty and shows only the
> > >blinking cursor. The screen shows the normal TTY log in prompt.
> >
> > I have now had a chance to find out more about the issue. I can reproduce this
> > both on a Debian 10 with Linux 4.19, or 5.2, as well as on an Ubuntu with
> > Linux 5.3.
> > As a temporary work-around, I have set the console font from „fixed” to
> > terminus in the largest font. I wonder how this might affect /dev/vcsu.
>
> Are you saying that this workaround "solved" the issue?

Yes, it does.

> What if you add the following to your brltty.conf instead:
>
> screen-parameters lx:unicode=no

Then I get "no screen" on my display.

> # The
> > Linux tty uses a framebuffer with an AMD GPU driver.
>
> What messages related to "Console" or "framebuffer" or "fb0" do you get
> from the dmesg command after boot?

I've attached the output below. Hopefully this is helpful at all, it was a bit
tedious to grep for three different terms :).

Thanks!
Sebastian
=== dmesg excerpt ===
[…]
[    0.093033] vt handoff: transparent VT on vt#7
[    0.093037] Console: colour dummy device 80x25
[    0.093042] printk: console [tty0] enabled
[    0.093055] ACPI: Core revision 20190703
[    0.093488] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635855245 ns
[    0.093553] APIC: Switch to symmetric I/O mode setup
[…]
[    0.433210] efifb: probing for efifb
[    0.433222] efifb: framebuffer at 0xc0000000, using 14400k, total 14400k
[    0.433223] efifb: mode is 2560x1440x32, linelength=10240, pages=1
[    0.433223] efifb: scrolling: redraw
[    0.433224] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
[    0.433267] Console: switching to colour frame buffer device 160x45
[    0.433280] fb0: EFI VGA frame buffer device
[…]
[    2.776945] amdgpu 0000:65:00.0: remove_conflicting_pci_framebuffers: bar 0: 0xc0000000 -> 0xcfffffff
[    2.776947] amdgpu 0000:65:00.0: remove_conflicting_pci_framebuffers: bar 2: 0xd0000000 -> 0xd01fffff
[    2.776949] amdgpu 0000:65:00.0: remove_conflicting_pci_framebuffers: bar 5: 0xd8e00000 -> 0xd8e3ffff
[    2.776950] checking generic (c0000000 e10000) vs hw (c0000000 10000000)
[    2.776951] fb0: switching to amdgpudrmfb from EFI VGA
[    2.777243] Console: switching to colour dummy device 80x25
[    2.777254] amdgpu 0000:65:00.0: vgaarb: deactivate vga console
[    2.777284] amdgpu 0000:65:00.0: enabling device (0106 -> 0107)
[…]
[    3.097386] [drm] fb mappable at 0xC1340000
[    3.097387] [drm] vram apper at 0xC0000000
[    3.097387] [drm] size 14745600
[    3.097387] [drm] fb depth is 24
[    3.097388] [drm]    pitch is 10240
[    3.097435] fbcon: amdgpudrmfb (fb0) is primary device
[    3.097482] Console: switching to colour frame buffer device 160x45
[    3.097495] amdgpu 0000:65:00.0: fb0: amdgpudrmfb frame buffer device
[    3.117995] EDAC MC0: Giving out device to module skx_edac controller Skylake Socket#0 IMC#0: DEV 0000:64:0a.0 (INTERRUPT)
[    3.118013] EDAC MC1: Giving out device to module skx_edac controller Skylake Socket#0 IMC#1: DEV 0000:64:0c.0 (INTERRUPT)
[    3.118404] input: HDA Intel PCH Rear Mic as /devices/pci0000:00/0000:00:1f.3/sound/card0/input15
[    3.118445] input: HDA Intel PCH Front Mic as /devices/pci0000:00/0000:00:1f.3/sound/card0/input16
[    3.118477] input: HDA Intel PCH Line Out as /devices/pci0000:00/0000:00:1f.3/sound/card0/input17
[    3.118508] input: HDA Intel PCH Front Headphone as /devices/pci0000:00/0000:00:1f.3/sound/card0/input18
[    3.138450] [drm] Initialized amdgpu 3.33.0 20150101 for 0000:65:00.0 on minor 0
[    3.249626] intel_rapl_common: Found RAPL domain package
[    3.249630] intel_rapl_common: Found RAPL domain dram
[    3.249630] intel_rapl_common: DRAM domain energy unit 15300pj
[    3.276836] audit: type=1400 audit(1574758071.210:2): apparmor="STATUS" operation="profile_load" profile="unconfined" name="lsb_release" pid=985 comm="apparmor_parser"
[    3.277110] audit: type=1400 audit(1574758071.210:3): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/snapd/snap-confine" pid=988 comm="apparmor_parser"
[    3.277111] audit: type=1400 audit(1574758071.210:4): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/snapd/snap-confine//mount-namespace-capture-helper" pid=988 comm="apparmor_parser"
[    3.277416] audit: type=1400 audit(1574758071.210:5): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/sbin/ippusbxd" pid=984 comm="apparmor_parser"
[    3.277552] audit: type=1400 audit(1574758071.214:6): apparmor="STATUS" operation="profile_load" profile="unconfined" name="nvidia_modprobe" pid=980 comm="apparmor_parser"
[    3.277555] audit: type=1400 audit(1574758071.214:7): apparmor="STATUS" operation="profile_load" profile="unconfined" name="nvidia_modprobe//kmod" pid=980 comm="apparmor_parser"
[    3.280038] audit: type=1400 audit(1574758071.214:8): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/bin/man" pid=987 comm="apparmor_parser"
[    3.280039] audit: type=1400 audit(1574758071.214:9): apparmor="STATUS" operation="profile_load" profile="unconfined" name="man_filter" pid=987 comm="apparmor_parser"
[…]