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Date: Mon, 06 Apr 2009 18:35:58 +0100
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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Subject: Re: [Qemu-devel] [6989] Fix display breakage when resizing the screen
	(v2) (Avi Kivity)
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To: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

Avi Kivity wrote:

> Avi Kivity wrote:
>>> Secondly it doesn't follow the basic idea behind the DisplayState
>>> surface: it is supposed to be a pixel surface provided by the vga
>>> emulator to the frontends, cirrus shouldn't have to care what size it 
>>> is.
>>> In fact cirrus emulates bitblit operations on the emulated framebuffer,
>>> not on the DisplayState surface; if it does so is a bug and should be 
>>> fixed.
>>>   
>> This happens through cirrus_do_copy(), which implies that the display 
>> surface is involved.  Is that wrong?
> 
> I think what you're saying is, we shouldn't call qemu_console_copy() in 
> cirrus_do_copy() if vga is not displayed on the console?
> 
> (and conversely, if it is displayed, we shouldn't call 
> cirrus_invalidate_region).
> 


I tried several times to manually reproduce the issue with no luck: if
no vnc clients are supposed to be connected, how do you make the cirrus
emulated hw do a bitblit?

In any case it makes sense that the problem is in qemu_console_copy()
rather than in the rop function itself that only operates on the
emulated framebuffer.
But calling qemu_console_copy() in cirrus_do_copy() shouldn't be risky
because before that, we call vga_hw_update() that should do the resize.

Without a better understanding of the bug I will refrain from making any
suggestion.