Re: Hyper-V Synthetic Video Frame Buffer Driver may distort top two lines of console

2014-03-06 Thread Brian Wong

On 3/6/2014 3:41 PM, Brian Wong wrote:

I've identified another possible bug in the Hyper-V drivers: When the
Hyper-V Synthetic Video Frame Buffer Driver is built into the kernel,
and the VM is paused and continued, the top two lines of the console may
become distorted. See the image at http://imgur.com/kIExFP3.

Can someone look into it?


Just to clarify, I can confirm this bug under both the patched Gentoo 
3.10.32 kernel and the vanilla 3.13.5 kernel (see the image at 
http://imgur.com/mYUTzgt). Is the framebuffer somehow getting corrupted?


--
Brian Wong
http://www.fierydragonlord.com
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RE: Hyper-V Synthetic Video Frame Buffer Driver may distort top two lines of console

2014-03-06 Thread KY Srinivasan


 -Original Message-
 From: Brian Wong [mailto:draconicpengu...@yahoo.com]
 Sent: Friday, March 7, 2014 3:19 AM
 To: KY Srinivasan; linux-kernel@vger.kernel.org
 Subject: Re: Hyper-V Synthetic Video Frame Buffer Driver may distort top
 two lines of console
 
 On 3/6/2014 4:05 PM, Brian Wong wrote:
  On 3/6/2014 3:41 PM, Brian Wong wrote:
  I've identified another possible bug in the Hyper-V drivers: When the
  Hyper-V Synthetic Video Frame Buffer Driver is built into the kernel,
  and the VM is paused and continued, the top two lines of the console
  may become distorted. See the image at http://imgur.com/kIExFP3.
 
  Can someone look into it?
Haiyang (copied here) will look into it.

Regards,

K. Y
 
  Just to clarify, I can confirm this bug under both the patched Gentoo
  3.10.32 kernel and the vanilla 3.13.5 kernel (see the image at
  http://imgur.com/mYUTzgt). Is the framebuffer somehow getting
 corrupted?
 
 
 The problem also reproduces under Kali Linux with kernel 3.12.6, but only on
 virtual consoles that are not hosting a graphical X session. The problem does
 not appear in X.
 
 --
 Brian Wong
 http://www.fierydragonlord.com
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Re: Hyper-V Synthetic Video Frame Buffer Driver may distort top two lines of console

2014-03-06 Thread Brian Wong

On 3/6/2014 4:05 PM, Brian Wong wrote:

On 3/6/2014 3:41 PM, Brian Wong wrote:

I've identified another possible bug in the Hyper-V drivers: When the
Hyper-V Synthetic Video Frame Buffer Driver is built into the kernel,
and the VM is paused and continued, the top two lines of the console may
become distorted. See the image at http://imgur.com/kIExFP3.

Can someone look into it?


Just to clarify, I can confirm this bug under both the patched Gentoo
3.10.32 kernel and the vanilla 3.13.5 kernel (see the image at
http://imgur.com/mYUTzgt). Is the framebuffer somehow getting corrupted?



The problem also reproduces under Kali Linux with kernel 3.12.6, but 
only on virtual consoles that are not hosting a graphical X session. The 
problem does not appear in X.


--
Brian Wong
http://www.fierydragonlord.com
--
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RE: Hyper-V Synthetic Video Frame Buffer Driver may distort top two lines of console

2014-03-06 Thread Haiyang Zhang


 -Original Message-
 From: KY Srinivasan
 Sent: Thursday, March 6, 2014 4:51 PM
 To: Brian Wong; linux-kernel@vger.kernel.org; Haiyang Zhang
 Subject: RE: Hyper-V Synthetic Video Frame Buffer Driver may distort top
 two lines of console
 
 
 
  -Original Message-
  From: Brian Wong [mailto:draconicpengu...@yahoo.com]
  Sent: Friday, March 7, 2014 3:19 AM
  To: KY Srinivasan; linux-kernel@vger.kernel.org
  Subject: Re: Hyper-V Synthetic Video Frame Buffer Driver may distort
  top two lines of console
 
  On 3/6/2014 4:05 PM, Brian Wong wrote:
   On 3/6/2014 3:41 PM, Brian Wong wrote:
   I've identified another possible bug in the Hyper-V drivers: When
   the Hyper-V Synthetic Video Frame Buffer Driver is built into the
   kernel, and the VM is paused and continued, the top two lines of
   the console may become distorted. See the image at
 http://imgur.com/kIExFP3.
  
   Can someone look into it?
 Haiyang (copied here) will look into it.
 

It's a known issue. The root cause is not very clear yet.
It doesn't affect system functions. But we will look into it 
further.

Thanks,
- Haiyang

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