[Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Avi Kivity]

On 01/10/2010 06:26 PM, SourceForge.net wrote:
> Initial Comment:
> So I am running using the VESA driver to run an Ubuntu 9.10 guest at 2560x1600 (I had to modify the xserver-video-vesa package to remove an internal screen limit of 2048x2048 in the xorg vesa driver) and everything works great except that the qemu vnc server appears to clip at this resolution. The problem goes away if I run 1900x1200 and it doesn't change if I run 16bit depth or 24bit depth.
>
> I have attached two screenshots, the first is vncing directly into qemu (which exhibits the problem) and the second is vncing to a vnc server I have running in the guest which doesn't have the problem.
>
> I poked around in vnc.c and couldn't see any limits but I feel like its a buffer limit of some kind.
>
> Also if you look very closely at the first image you can see that the first row is drawn correctly all the way across but subsequent rows are not.
>
> If you need more information doesn't hesitate to ask.
>
>    

Anthony, can you take a look at this?  Seems like a serious issue, could 
find nothing obvious in vnc.c.

> ----------------------------------------------------------------------
>
>    
>> Comment By: Avi Kivity (avik)
>>      
> Date: 2010-01-10 18:26
>
> Message:
> Confirmed with vncviewer and vinagre, so unlikely to be a client problem.
>
> ----------------------------------------------------------------------
>
> Comment By: Avi Kivity (avik)
> Date: 2010-01-10 16:17
>
> Message:
> The cropping is 512 pixels wide, the correct area is 2048 pixels wide, so
> it does look like some kind of limit.
>
> ----------------------------------------------------------------------
>
> Comment By: SourceForge Robot (sf-robot)
> Date: 2009-12-28 04:20
>
> Message:
> This Tracker item was closed automatically by the system. It was
> previously set to a Pending status, and the original submitter
> did not respond within 14 days (the time period specified by
> the administrator of this Tracker).
>
> ----------------------------------------------------------------------
>
> Comment By: Matthew Colyer (mcsoccer)
> Date: 2009-12-17 05:18
>
> Message:
> The blocks do not show up when run in SDL mode. So I believe the problem is
> still somehow related to the VNC server.
>
> ----------------------------------------------------------------------
>
> Comment By: Avi Kivity (avik)
> Date: 2009-12-13 12:29
>
> Message:
> Does it work well with SDL?  Maybe the problem is not vnc related.
>
> ----------------------------------------------------------------------
>
> You can respond by visiting:
> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2907597&group_id=180599
> --
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>    


-- 
error compiling committee.c: too many arguments to function

[Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Anthony Liguori]

On 01/10/2010 10:30 AM, Avi Kivity wrote:
> On 01/10/2010 06:26 PM, SourceForge.net wrote:
>> Initial Comment:
>> So I am running using the VESA driver to run an Ubuntu 9.10 guest at 
>> 2560x1600 (I had to modify the xserver-video-vesa package to remove 
>> an internal screen limit of 2048x2048 in the xorg vesa driver) and 
>> everything works great except that the qemu vnc server appears to 
>> clip at this resolution. The problem goes away if I run 1900x1200 and 
>> it doesn't change if I run 16bit depth or 24bit depth.
>>
>> I have attached two screenshots, the first is vncing directly into 
>> qemu (which exhibits the problem) and the second is vncing to a vnc 
>> server I have running in the guest which doesn't have the problem.
>>
>> I poked around in vnc.c and couldn't see any limits but I feel like 
>> its a buffer limit of some kind.
>>
>> Also if you look very closely at the first image you can see that the 
>> first row is drawn correctly all the way across but subsequent rows 
>> are not.
>>
>> If you need more information doesn't hesitate to ask.
>>
>
> Anthony, can you take a look at this?  Seems like a serious issue, 
> could find nothing obvious in vnc.c.

VNC_MAX_WIDTH and VNC_MAX_HEIGHT in vnc.h are currently defined to 
2048.  We do dirty tracking with a bitmap and that bitmap is currently a 
fixed size.

2048 is bigger than any physical screen that I know of so I assume this 
is a multiple monitor scenario.  Long term, I think exposing multiple 
monitors to the guest is a better approach for this kind of functionality.

Since these resolutions for a single screen don't really exist, this is 
largely an untested path within the guest.

Regards,

Anthony Liguori

[Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Avi Kivity]

On 01/11/2010 03:53 PM, Anthony Liguori wrote:
>> Anthony, can you take a look at this?  Seems like a serious issue, 
>> could find nothing obvious in vnc.c.
>
>
> VNC_MAX_WIDTH and VNC_MAX_HEIGHT in vnc.h are currently defined to 
> 2048.  We do dirty tracking with a bitmap and that bitmap is currently 
> a fixed size.
>
> 2048 is bigger than any physical screen that I know of so I assume 
> this is a multiple monitor scenario.  Long term, I think exposing 
> multiple monitors to the guest is a better approach for this kind of 
> functionality.
>
> Since these resolutions for a single screen don't really exist, this 
> is largely an untested path within the guest.

Google suggests such screens do exist, and -vga std (at least in 
qemu-kvm) supports them.

I've asked the reporter to play with VNC_MAX_WIDTH.

-- 
error compiling committee.c: too many arguments to function

[Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Avi Kivity]

On 01/11/2010 04:30 PM, Avi Kivity wrote:
>>
>> VNC_MAX_WIDTH and VNC_MAX_HEIGHT in vnc.h are currently defined to 
>> 2048.  We do dirty tracking with a bitmap and that bitmap is 
>> currently a fixed size.
>>
>> 2048 is bigger than any physical screen that I know of so I assume 
>> this is a multiple monitor scenario.  Long term, I think exposing 
>> multiple monitors to the guest is a better approach for this kind of 
>> functionality.
>>
>> Since these resolutions for a single screen don't really exist, this 
>> is largely an untested path within the guest.
>
>
> Google suggests such screens do exist, and -vga std (at least in 
> qemu-kvm) supports them.
>
> I've asked the reporter to play with VNC_MAX_WIDTH.
>

The reporter confirms that increasing V_M_W fixes the problem.

-- 
error compiling committee.c: too many arguments to function

Re: [Qemu-devel] Re: [ kvm-Bugs-2907597 ] qemu vnc server clips at 2560x1600

[Jernej Simončič]

On Monday, January 11, 2010, 14:53:05, Anthony Liguori wrote:

> 2048 is bigger than any physical screen that I know of so I assume this
> is a multiple monitor scenario.

30" TFTs have resolution 2560x1600.

Speaking of large resolutions, I just tried 2360x1770 (the largest
offered by VMWare VGA driver in Win2003 x64), and in my case, the left
side of the screen is clipped, while the right side is mostly fine
(only the mouse pointer is leaving trails behind):
<http://img27.imageshack.us/img27/2760/image1ud.png>

-- 
< Jernej Simončič ><><><><>< http://eternallybored.org/ >

What the gods get away with, the cows don't.
       -- The Aquinas Axiom