[OE-core] [OE-Core][RFC 0/2] qemuarm64: cleanup and Add graphics support

Jon Mason jdmason at kudzu.us
Thu Feb 28 04:15:39 UTC 2019

This series is dependent on the yocto-kernel-cache RFC series similarly
named.  See

This series cleans up the hvc0 respawning issue, by removing the
reference in meta/conf/machine/qemuarm64.conf.  So virtio console will
not work, but I don't think it was properly working before.  A bug
should be opened to track this and correct it when a solution is found.

Also, graphics support is added by using the QEMU VGA device, which
emulates a Bochs VGA PCI adapter.  Virtio would be a superior
implementation (in theory), but I was unable to get it working fully.  A
bug should be opened to track this and switch to using virtio when the
issue(s) can be resolved.

Finally, when starting the graphics, a kernel warning is issued.  It
is not fatal and graphics work despite the warning.  However, this might
be unacceptable.  For the record, it is:

[   18.370702] ------------[ cut here ]------------
[   18.382099] WARNING: CPU: 0 PID: 446 at drivers/gpu/drm/ttm/ttm_bo_vm.c:303 ttm_bo_vm_open+0x3c/0x4c
[   18.383267] Modules linked in:
[   18.383789] CPU: 0 PID: 446 Comm: Xorg Not tainted 4.19.19-yocto-standard #1
[   18.383964] Hardware name: Generic DT based system
[   18.384508] [<c021306c>] (unwind_backtrace) from [<c020d174>] (show_stack+0x20/0x24)
[   18.384719] [<c020d174>] (show_stack) from [<c09964a0>] (dump_stack+0x84/0xa4)
[   18.384904] [<c09964a0>] (dump_stack) from [<c0231dd0>] (__warn+0xe8/0x104)
[   18.385114] [<c0231dd0>] (__warn) from [<c0232180>] (warn_slowpath_null+0x4c/0x58)
[   18.385300] [<c0232180>] (warn_slowpath_null) from [<c072b408>] (ttm_bo_vm_open+0x3c/0x4c)
[   18.385499] [<c072b408>] (ttm_bo_vm_open) from [<c0230718>] (copy_process.part.3+0x13c4/0x17f0)
[   18.385703] [<c0230718>] (copy_process.part.3) from [<c0230ce8>] (_do_fork+0xc8/0x414)
[   18.385907] [<c0230ce8>] (_do_fork) from [<c0231154>] (sys_clone+0x30/0x38)
[   18.386108] [<c0231154>] (sys_clone) from [<c0201000>] (ret_fast_syscall+0x0/0x4c)
[   18.386308] Exception stack(0xde279fa8 to 0xde279ff0)
[   18.386477] 9fa0:                   b6ef7078 b6f03000 01200011 00000000 00000000 00000000
[   18.386672] 9fc0: b6ef7078 b6f03000 b6ef74d0 00000078 00000000 b6ef7010 0051b03d be9bc9fc
[   18.386857] 9fe0: 00000078 be9ba8a8 b6ad564d b6a7ac46
[   18.387096] ---[ end trace e8a5e15e3b7db8a9 ]---

Given these number of issues, I wanted to post this as a request for
comment to see if this is acceptable to the community.  If it is
acceptable, I will open the bugs mentioned above.

I have made similar modifications to qemuarma15, and can resubmit them
if the solution above is acceptable.  However, I thought using qemuarm64
was a cleaner way to show what was done and start the dialog.


Jon Mason (2):
  qemuarm64: fix hvc0 error and cleanup
  qemuarm64: Add graphics support

 meta/conf/machine/qemuarm64.conf | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)


More information about the Openembedded-core mailing list