[Qemu-devel] [Bug 1087974] [NEW] [regression] vnc tight png produces garbled output

[Qemu-devel] [Bug 1087974] [NEW] [regression] vnc tight png produces garbled output

[Tim Hardeck]

Public bug reported:

VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

** Affects: qemu
     Importance: Undecided
         Status: New

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Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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Re: [Qemu-devel] [Bug 1087974] [NEW] [regression] vnc tight png produces garbled output

[Stefan Hajnoczi]

On Sat, Dec 8, 2012 at 12:46 PM, Tim Hardeck <thardeck@suse.de> wrote:
> Public bug reported:
>
> VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
> I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

Hi Tim,
If you have a few minutes please use git-bisect(1) to identify the
commit that causes the regression.

The rough steps are:
1. Verify that qemu.git/master is broken and find an older commit
where it works.
2. Use git-bisect(1) to binary search the commit history between these
two points - it will leave you with the commit that caused the
regression.

Here some quick links to get you started:
http://git-scm.com/book/en/Git-Tools-Debugging-with-Git#Binary-Search
http://blog.evan.pro/getting-started-with-git-bisect-in-60-seconds

Stefan

[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Tim Hardeck]

47683d669f993308c2b84bed4ce64aafb5d7ced4 is the first bad commit
commit 47683d669f993308c2b84bed4ce64aafb5d7ced4
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Thu Oct 11 12:04:33 2012 +0200

    pixman/vnc: remove rgb_prepare_row* functions

    Let pixman do it instead.

    Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

:040000 040000 653d58e66bf3a2d8240b2f9176979c44ccd720e1
6b6e367a8522cb58b42ad8f204387a354d3b3d00 M  ui


Just reverting this particular commit isn't enough thou but it is connected.

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Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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Re: [Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Stefan Hajnoczi]

On Mon, Dec 10, 2012 at 03:54:58PM -0000, Tim Hardeck wrote:
> 47683d669f993308c2b84bed4ce64aafb5d7ced4 is the first bad commit
> commit 47683d669f993308c2b84bed4ce64aafb5d7ced4
> Author: Gerd Hoffmann <kraxel@redhat.com>
> Date:   Thu Oct 11 12:04:33 2012 +0200
> 
>     pixman/vnc: remove rgb_prepare_row* functions
> 
>     Let pixman do it instead.
> 
>     Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> 
> :040000 040000 653d58e66bf3a2d8240b2f9176979c44ccd720e1
> 6b6e367a8522cb58b42ad8f204387a354d3b3d00 M  ui
> 
> 
> Just reverting this particular commit isn't enough thou but it is connected.

This suggests the conversion to pixman has introduced the bug.

Tim: can you provide steps to reproduce the bug?

Stefan

Re: [Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Gerd Hoffmann]

On 12/11/12 09:57, Stefan Hajnoczi wrote:
> On Mon, Dec 10, 2012 at 03:54:58PM -0000, Tim Hardeck wrote:
>> 47683d669f993308c2b84bed4ce64aafb5d7ced4 is the first bad commit
>> commit 47683d669f993308c2b84bed4ce64aafb5d7ced4
>> Author: Gerd Hoffmann <kraxel@redhat.com>
>> Date:   Thu Oct 11 12:04:33 2012 +0200
>>
>>     pixman/vnc: remove rgb_prepare_row* functions
>>
>>     Let pixman do it instead.
>>
>>     Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>>
>> :040000 040000 653d58e66bf3a2d8240b2f9176979c44ccd720e1
>> 6b6e367a8522cb58b42ad8f204387a354d3b3d00 M  ui
>>
>>
>> Just reverting this particular commit isn't enough thou but it is connected.
> 
> This suggests the conversion to pixman has introduced the bug.

Quite possible.  I've tested tight via 'vncviewer
PreferredEncoding=Tight', but that doesn't force png, so there is a
chance for issues I havn't seen.

> Tim: can you provide steps to reproduce the bug?

That will certainly help fixing.

Also: How garbled?  Totally messed up?  Just colors wrong?  Any other
visible pattern?

cheers,
  Gerd

[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Tim Hardeck]

* make sure that qemu is compiled with --enable-vnc-png

* git clone git://github.com/kanaka/noVNC
* edit include/rfb.js at line 50 and comment out or remove all encodings above "['TIGHT_PNG',        -260 ],"
* open vnc.html in Firefox or Chrome

*apply either my patch to QEMU https://lists.nongnu.org/archive/html
/qemu-devel/2012-12/msg00869.html or use Websockify
https://github.com/kanaka/websockify to get Websocket support.

* in case of my patch run QEMU with  `-vnc :0,websocket` and connect
with noVNC to port 5700.

* in case of Websockify run QEMU with `./websockify.py 5900 -- qemu-
system-x86_64 -vnc :0` and connect to port 5900

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https://bugs.launchpad.net/bugs/1087974

Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Tim Hardeck]

** Attachment added: "screenshot of the issue"
   https://bugs.launchpad.net/qemu/+bug/1087974/+attachment/3457223/+files/tight-png-compression-issue.png

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https://bugs.launchpad.net/bugs/1087974

Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

To manage notifications about this bug go to:
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Re: [Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Gerd Hoffmann]

On 12/11/12 11:09, Tim Hardeck wrote:
> * make sure that qemu is compiled with --enable-vnc-png
> 
> * git clone git://github.com/kanaka/noVNC
> * edit include/rfb.js at line 50 and comment out or remove all encodings above "['TIGHT_PNG',        -260 ],"
> * open vnc.html in Firefox or Chrome
> 
> *apply either my patch to QEMU https://lists.nongnu.org/archive/html
> /qemu-devel/2012-12/msg00869.html or use Websockify
> https://github.com/kanaka/websockify to get Websocket support.
> 
> * in case of my patch run QEMU with  `-vnc :0,websocket` and connect
> with noVNC to port 5700.
> 
> * in case of Websockify run QEMU with `./websockify.py 5900 -- qemu-
> system-x86_64 -vnc :0` and connect to port 5900

Hmm, doesn't reproduce here (using websockify proxy).

--- a/include/rfb.js
+++ b/include/rfb.js
@@ -48,8 +48,8 @@ var that           = {},  // Public API methods

     // In preference order
     encodings      = [
-        ['COPYRECT',         0x01 ],
-        ['TIGHT',            0x07 ],
+//        ['COPYRECT',         0x01 ],
+//        ['TIGHT',            0x07 ],
         ['TIGHT_PNG',        -260 ],
         ['HEXTILE',          0x05 ],
         ['RRE',              0x02 ],


cheers,
  Gerd

[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Tim Hardeck]

If you had opened vnc.html before the rfb.js might be still in the browser cache, at least I had a similar issue once.
I have tested this with Chrome but I think it happened in Firefox too.

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https://bugs.launchpad.net/bugs/1087974

Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Tim Hardeck]

The patch does fix the issue for me, thanks.

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https://bugs.launchpad.net/bugs/1087974

Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  New

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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[Qemu-devel] [Bug 1087974] Re: [regression] vnc tight png produces garbled output

[Thomas Huth]

Gerd's patch had been included here:
http://git.qemu.org/?p=qemu.git;a=commitdiff;h=bc210eb163b162ff2
==> Setting status to "Fix released"

** Changed in: qemu
       Status: New => Fix Released

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Title:
  [regression] vnc tight png produces garbled output

Status in QEMU:
  Fix Released

Bug description:
  VNC Tight PNG compression did work fine two or three month ago but don't anymore. Now when Tight PNG is used parts of the desktop are shown but they are scrambled together.
  I have always tested this feature against QEMU git with noVNC by only allowing Tight PNG compression.

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