[Qemu-devel] [Bug 922076] [NEW] doesn't clear screen on boot

[Qemu-devel] [Bug 922076] [NEW] doesn't clear screen on boot

[Askar Safin]

Public bug reported:

When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu
window, it shows message "Starting Seabios (version 0.5.1-2010...)", and
then Linux writes messages like "Loading, please wait..." on top of
previous message!

For example, I can see "Loading, please wait...on 0.5.1-2010...)"

So, Qemu doesn't clean screan before booting OS.

Moreover, when I start Linux via "qemu /disk-image", Qemu shows
"Starting Seabios (version 0.5.1-2010...)", then switches to graphical
mode, shows GRUB, then switches back to text mode and shows "Starting
Seabios" again! And again Linux prints messages on top of Seabios
messages, and we see a mix of symbols on screen.

Also, I found another bug! I am learning now to write kernels. And I see
that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't clean
first charaster of screen in Qemu in "-curses" mode! If I want to real
clean this charaster, I must type "*(char *)0xb8000 = ' '".

I attach a kernel (x86, multiboot) with this bug. Just type "make" (you
need gcc) and "qemu -curses -kernel kernel". You will see that screen is
not cleared, but kernel tries to clean it. If you change 0 to ' ', all
will work!

** Affects: qemu
     Importance: Undecided
         Status: New

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Title:
  doesn't clear screen on boot

Status in QEMU:
  New

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu
  window, it shows message "Starting Seabios (version 0.5.1-2010...)",
  and then Linux writes messages like "Loading, please wait..." on top
  of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

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[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

** Attachment added: "kernel code. this kernel makes qemu bugs visible"
   https://bugs.launchpad.net/bugs/922076/+attachment/2694574/+files/kernel.tar

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Title:
  doesn't clear screen on boot

Status in QEMU:
  New

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu
  window, it shows message "Starting Seabios (version 0.5.1-2010...)",
  and then Linux writes messages like "Loading, please wait..." on top
  of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

UPDATE: The second bug (which is started with "Also, I found another
bug! I am learning...") is fixed in 1.4.0

About the first bug: screen clears on real hardware, so it is really
bug. Also, it is reproducible with Qemu 1.4.0 and Qemu
5e3a0f418c4d57399778cee0b55aebfb663b6425.

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https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  New

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu
  window, it shows message "Starting Seabios (version 0.5.1-2010...)",
  and then Linux writes messages like "Loading, please wait..." on top
  of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

** Description changed:

- When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu
- window, it shows message "Starting Seabios (version 0.5.1-2010...)", and
- then Linux writes messages like "Loading, please wait..." on top of
+ When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu window
+ appears and it shows message "Starting Seabios (version 0.5.1-2010...)",
+ and then Linux writes messages like "Loading, please wait..." on top of
  previous message!
  
  For example, I can see "Loading, please wait...on 0.5.1-2010...)"
  
  So, Qemu doesn't clean screan before booting OS.
  
  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.
  
  Also, I found another bug! I am learning now to write kernels. And I see
  that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't clean
  first charaster of screen in Qemu in "-curses" mode! If I want to real
  clean this charaster, I must type "*(char *)0xb8000 = ' '".
  
  I attach a kernel (x86, multiboot) with this bug. Just type "make" (you
  need gcc) and "qemu -curses -kernel kernel". You will see that screen is
  not cleared, but kernel tries to clean it. If you change 0 to ' ', all
  will work!

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https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  New

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

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https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Thomas Huth]

Does this problem still exist with the latest version of QEMU? Which
interface type are you using (SDL, gtk, ...)? Can you please provide
your full command line and build options?

** Changed in: qemu
       Status: New => Incomplete

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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  Incomplete

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

The bug still exists in qemu 2.7 (version present in my debian stretch).
I was not able reproduce the bug with booting kernel directly with 2.7 (-kernel ...), but booting disk image causes the bug.

So, I have debian gnu/linux stretch amd64. debian package qemu-
system-x86 1:2.7+dfsg-3+b1. I run my host system in qemu (i. e. I run in
qemu same system that running on the host) using well known "-snapshot
-drive file=/dev/sda" trick. Precise command line is:

kdesudo -c "exec qemu-system-x86_64 -m 1024M -enable-kvm -daemonize
-snapshot -drive file=/dev/sda,cache=none,format=raw"

Qemu appears and I see usual "SeaBIOS (version
1.9.3-20161025_171302-gandalf)" as you can see at screenshot
Screenshot_20161216_005817.png .

Then qemu switches to grub.

And then qemu switches to text mode back. And fsck prints to console:
"/dev/sda2: recovering journal", but this words appears on top of that
SeaBIOS self-adver., so we have the following words mixture:

/dev/sda2: recovering journal25_171302-gandalf)

I use sdl. I don't know build option, this is qemu from debian package

** Attachment added: "Screenshot_20161216_005817.png"
   https://bugs.launchpad.net/qemu/+bug/922076/+attachment/4792204/+files/Screenshot_20161216_005817.png

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https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  Incomplete

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

This is Screenshot_20161216_005859.png , screenshot with grub

** Attachment added: "Screenshot_20161216_005859.png"
   https://bugs.launchpad.net/qemu/+bug/922076/+attachment/4792205/+files/Screenshot_20161216_005859.png

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  Incomplete

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Askar Safin]

And this is Screenshot_20161216_005917.png . Here (after grub) we see
"recovering journal" on top of seabios string

** Attachment added: "Screenshot_20161216_005917.png"
   https://bugs.launchpad.net/qemu/+bug/922076/+attachment/4792206/+files/Screenshot_20161216_005917.png

-- 
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devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  Incomplete

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Qemu-devel] [Bug 922076] Re: doesn't clear screen on boot

[Thomas Huth]

** Changed in: qemu
       Status: Incomplete => Triaged

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https://bugs.launchpad.net/bugs/922076

Title:
  doesn't clear screen on boot

Status in QEMU:
  Triaged

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions

[Bug 922076] Re: doesn't clear screen on boot

[Thomas Huth]

This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/87


** Changed in: qemu
       Status: Triaged => Expired

** Bug watch added: gitlab.com/qemu-project/qemu/-/issues #87
   https://gitlab.com/qemu-project/qemu/-/issues/87

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Title:
  doesn't clear screen on boot

Status in QEMU:
  Expired

Bug description:
  When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu
  window appears and it shows message "Starting Seabios (version
  0.5.1-2010...)", and then Linux writes messages like "Loading, please
  wait..." on top of previous message!

  For example, I can see "Loading, please wait...on 0.5.1-2010...)"

  So, Qemu doesn't clean screan before booting OS.

  Moreover, when I start Linux via "qemu /disk-image", Qemu shows
  "Starting Seabios (version 0.5.1-2010...)", then switches to graphical
  mode, shows GRUB, then switches back to text mode and shows "Starting
  Seabios" again! And again Linux prints messages on top of Seabios
  messages, and we see a mix of symbols on screen.

  Also, I found another bug! I am learning now to write kernels. And I
  see that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't
  clean first charaster of screen in Qemu in "-curses" mode! If I want
  to real clean this charaster, I must type "*(char *)0xb8000 = ' '".

  I attach a kernel (x86, multiboot) with this bug. Just type "make"
  (you need gcc) and "qemu -curses -kernel kernel". You will see that
  screen is not cleared, but kernel tries to clean it. If you change 0
  to ' ', all will work!

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/922076/+subscriptions