Re: [Xen-devel] blank screen VGA or Serial while linux boot

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Thu, Dec 29, 2016 at 06:44:00PM +0100, Daniele Palumbo wrote:
> Il giorno 29 dic 2016, alle ore 15:49, Konrad Rzeszutek Wilk 
> <konrad.wilk@xxxxxxxxxx> ha scritto:
> 
> Ty for the reply Konrad,
> 
> > On Wed, Dec 28, 2016 at 03:17:20PM +0100, Daniele Palumbo wrote:
> >> 
> >> GRUB_CMDLINE_LINUX="xencons=xvc console=xvc0 console=hvc0 console=tty1 
> >> earlyprintk=xen nomodeset"
> > You can remove the 'xencons' and 'console=xvc0’
> 
> about the slides, what is xvc0 useful for? (a link is more then welcome)

I can't remember.  It used be some driver but it never got upstreamed.
> 
> >> Seems like hvc0 contains only serial messages.
> > 
> > Right, that is what you should see on the iLOM.
> 
> Uhm,
> https://wiki.xenproject.org/wiki/Xen_Serial_Console
> Say:
> Pv_ops dom0 Linux kernel is configured to use the Xen (hvc0) console. Dom0 
> Linux kernel console output will go to the serial console through Xen, so 
> both Xen hypervisor and dom0 linux kernel output will go to the same serial 
> console.
> 
> Why hvc0 should be only in serial?

It actually just transports the characters to XEn. Xen can display
it via VGA or serial console. Usually it goes through the serial port.
> 
> >> Really willing to understand how to get the proper output on both serial 
> >> and VGA.
> > 
> > If you really really want that you can do:
> > 
> > CMD_CMDLINE_LINUX="console=hvc0"
> > 
> > GRUB_CMDLINE_XEN="console=com1,vga vga=text-80x60,keep      conswitch=ax
> > console_to_ring”
> 
> Tried.
> Only kernel logs in VGA, not on iLOM.
> 
> Plus, iLOM console not responding to keyboard.
> 
> Getting lost.
> 
> Any other hint?

Sorry :-(
> 
> Thanks,
> Daniele
> 
> Serial logs:
> XEN) Xen version 4.6.4 (@local.lipinutragen.it) (x86_64-pc-linux-gnu-gcc 
> (Gentoo 4.9.4 p1.0, pie-0.6.4) 4.9.4) debug=n Sat Dec 24 12:42:18 CET 2016
> (XEN) Latest ChangeSet: Gentoo GNU/Linux                                      
> *
> (XEN) Bootloader: GRUB 2.02~beta3ervisor                                      
> *
> (XEN) Command line: cpuidle dom0_mem=1024M,max:2048M loglvl=all 
> guest_loglvl=all com1=9600,8n1 console=com1,vga vga=text-80x60,keep 
> conswitch=ax console_to_ring86+ 4.20                                          
>                   **
> (XEN) Video 
> information:*******************************************************
> (XEN)  VGA is text mode 80x60, font 8x8
> (XEN)  VBE/DDC methods: none; EDID transfer time: 1 secondshted.
> (XEN)  EDID info not retrieved because no DDC retrieval method detected
> (XEN) Disc information: `c' for a command-line.
> (XEN)  Found 1 MBR signatures
> (XEN)  Found 1 EDD information structures
> (XEN) Xen-e820 RAM map:
> [...]
> (XEN) NX (Execute Disable) protection active
> (XEN) *** LOADING DOMAIN 0 ***
> (XEN)  Xen  kernel: 64-bit, lsb, compat32
> (XEN)  Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x1d44000
> (XEN) PHYSICAL MEMORY ARRANGEMENT:
> (XEN)  Dom0 alloc.:   0000000312000000->0000000314000000 (253134 pages to be 
> allocated)
> (XEN)  Init. ramdisk: 000000031fcce000->000000031ffff6b8
> (XEN) VIRTUAL MEMORY ARRANGEMENT:
> (XEN)  Loaded kernel: ffffffff81000000->ffffffff81d44000
> (XEN)  Init. ramdisk: 0000000000000000->0000000000000000
> (XEN)  Phys-Mach map: 0000008000000000->0000008000200000
> (XEN)  Start info:    ffffffff81d44000->ffffffff81d444b4
> (XEN)  Page tables:   ffffffff81d45000->ffffffff81d58000
> (XEN)  Boot stack:    ffffffff81d58000->ffffffff81d59000
> (XEN)  TOTAL:         ffffffff80000000->ffffffff82000000
> (XEN)  ENTRY ADDRESS: ffffffff81aa71f0
> (XEN) Dom0 has maximum 8 VCPUs
> (XEN) Scrubbing Free RAM on 1 nodes using 8 CPUs
> (XEN) .............done.
> (XEN) Initial low memory virq threshold set at 0x4000 pages.
> (XEN) Std. Loglevel: All
> (XEN) Guest Loglevel: All
> (XEN) Xen is keeping VGA console.
> (XEN) *** Serial input -> Xen (type 'CTRL-a' three times to switch input to 
> DOM0)
> (XEN) Freed 316kB init memory.
> mapping kernel into physical memory
> about to get started...
> (XEN) PCI add device 0000:00:00.0
> […]
> (XEN) PCI add device 0000:0c:05.0
> (XEN) Monitor-Mwait will be used to enter C1 state
> (XEN) Monitor-Mwait will be used to enter C2 state
> (XEN) Monitor-Mwait will be used to enter C3 state
> 
> 
> This is hostname (Linux x86_64 4.4.26-gentoo-Dom0-44-r2) 17:38:29, on hvc0
> 
> hostname login:
> 
> 



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