> From: Paul Menzel <paulepan...@users.sourceforge.net> > Sent: Thursday, August 9, 2018 12:30 AM > ... > > 4. What's the best way to debug grub_video_set_mode()? > > grub_dprintf() can't output anything in this function. > > Why? Because the display is not working? Hi Paul, Actually it works -- it looks somehow I was careless... I'm sorry!
> > Does grub support remote debugging via network? > > I know gdb can debug grub in Qemu, but here the issue looks like > > Hyper-V specific. > > If Hyper-V can emulate a serial port, then this should be one way to > go. Something like below for `/etc/default/grub`. > > GRUB_TERMINAL="console serial" > GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200" This serial port works very well for me. Thanks for sharing the trick! > > Paul About my original questions, it looks grub is doing right here: sometimes the VM can have "linux_gfx_mode=text", and if this happens, it looks correct for grub to set grub_video_adapter_active to NULL. However, I believe the line grub_memset (&mode_info, 0, sizeof (mode_info)); is unnecessary, and the commnt before the line grub_video_adapter_active = NULL; may seem incorrect. Of course, this is harmless. Thanks, -- Dexuan _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
