Le 10/02/2025 à 11:19, Carsten Haitzler a écrit :
If I guess correctly what's happening with my test: X clients never get
this error, and so they wait. Is that it?
they should...
strace would be the next port of call - but i shall assume they are sitting in
select/epoll waiting on something.
find the simplest app you can that doesn't work and i guess it's time to dig.
in fact trying your socat thing here.. a lot of things work. libreoffice works.
gedit works. my stuff (that does ximage fallback) works. anything qt does
not... in fact... i think i spotted the problem. simplest thing that doesn't
work:
glxgears
i have not dug much, but it seems qt is trying to use gl ... and thus anything
using qt is not working. gl is hanging.
so there's your core problem... without digging more i can't be sure but
getting gl to work remotely these days is not a great idea :)
nothing to do with shm. it's opengl. :)
I wonder if there aren't two (similar but distinct) problems, one with
GLX (or DRI?), the other with MIT-SHM
- glxinfo (rather minimalist), seems to wait for some reply :
$ DISPLAY=localhost:1 xtrace -n glxinfo
../..
000:<:0009: 12: GLX-Request(152,19): glXQueryServerString
context_tag=0x00000000 name=unknown:0x000020f6
000:>:0009:40: Reply to glXQueryServerString: string='mesa'
000:<:000a: 12: Request(98): QueryExtension name='GLX'
000:>:000a:32: Reply to QueryExtension: present=true(0x01)
major-opcode=152 first-event=95 first-error=158
000:<:000b: 12: Request(98): QueryExtension name='GLX'
000:>:000b:32: Reply to QueryExtension: present=true(0x01)
major-opcode=152 first-event=95 first-error=158
000:<:000c: 12: GLX-Request(152,7): glXQueryVersion
client_major_version=1 client_minor_version=4
000:>:000c:32: Reply to glXQueryVersion: server_major_version=1
server_minor_version=4
000:<:000d: 12: Request(98): QueryExtension name='DRI3'
000:<:000e: 16: Request(98): QueryExtension name='Present'
000:>:000d:32: Reply to QueryExtension: present=true(0x01)
major-opcode=149 first-event=0 first-error=0
000:>:000e:32: Reply to QueryExtension: present=true(0x01)
major-opcode=148 first-event=0 first-error=0
000:<:000f: 12: DRI3-Request(149,0): QueryVersion major_version=1
minor_version=2
000:<:0010: 12: Present-Request(148,0): QueryVersion majorVersion=1
minorVersion=2
000:>:000f:32: Reply to QueryVersion: major-version=1 minor-version=2
000:>:0010:32: Reply to QueryVersion: majorVersion=1 minorVersion=2
000:<:0011: 12: DRI3-Request(149,1): Open drawable=0x000003e2 provider=0
000:>:0011:32: Reply to Open: nfd=1
^C
$
- Xephyr (not so minimalist but well known) :
$ DISPLAY=localhost:1 xtrace -n Xephyr :20
../..
000:<:0010: 16: Request(98): QueryExtension name='MIT-SHM'
000:>:0010:32: Reply to QueryExtension: present=true(0x01)
major-opcode=130 first-event=65 first-error=128
000:<:0011: 4: MIT-SHM-Request(130,0): QueryVersion
000:>:0011:32: Reply to QueryVersion: major-version=1 minor-version=2
uid=0 gid=0 pixmap-format=ZPixmap(0x02)
000:<:0012: 16: MIT-SHM-Request(130,7): UNKNOWN opcode=0x82 opcode2=0x07
unparsed-data=0x05,0x00,0x40,0x04,0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00;
000:>:0012:32: unexpected Reply: data1=0x01 data2=0x01
unparsed-data=0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00;
^C
$
But disabling SHM makes it working (slow, but works):
$ DISPLAY=localhost:1 XEPHYR_NO_SHM=true xtrace -n Xephyr :20
- My very first need is for using wireshark (definitively not
minimalist, and with Qt)
It opens a window, but draws nothing.
... very mysterious to me...
Unless there's some other underlying reason?
