Re: mgag200 driver does not work properly with Xen

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Jan 02, 2013 at 01:23:27PM -0300, Fernando Luiz Chaves Xavier Matos wrote:
> When using Xen Hypervisor, the video goes very slow after module load in
> console.
> Xorg does not run.
> 
> My boot process (in kernel 3.7.1 from elrepo, my default kernel.):
> 1. Hypervisor is loaded (from here, the screen resolution is 640x480 - text
> scrolling fast)
> 2. Kernel is loaded
> 3. mgag200 module is loaded

>From the dmesg (https://bugzilla.kernel.org/attachment.cgi?id=90181)

I see:

[   17.652965] fbcon: mgadrmfb (fb0) is primary device
[   18.032813] [drm] mga base 0

So it looks like the mgadrmfb is actually in usage?

> 4. Screens enter native resolution (from here, the screen resolution is
> 1280x768 - text scrolling is slow..).

That could be due to using the MGADRMFB instead of the DRM one. But
more worrysime is this (https://bugzilla.kernel.org/attachment.cgi?id=89931):

[   445.347] (EE) MGA(0): V_BIOS address 0x0 out of range

which seems to be wrong. Let me ask you on the Bugzilla
(https://bugzilla.kernel.org/show_bug.cgi?id=52121)

for the baremetal bootup to get an idea of what it gets.

> 5. Starting Xorg gives me: "failed to activate core devices".
> 
> Without Xen, the video works great, Xorg starts, everything works fast and
> good.
> 
> Hardware:
> Motherboard: S1200BTLR
> Onboard video: ServerEngines LLC Pilot III (as written in manual)
> CPU: Intel Xeon E3-1270v2
> 
> Software:
> OS: Centos 6.3 64-bit
> Xen: 4.2.1
> 
> Kernels tested (all with Xen Hypervisor Loaded - except 2.6.32):
> 
> Kernel 2.6.32-279 (shipped with CentOS - does not support XEN_DOM0):
> - Screen is fast, but with 640x480 resolution.
> - Xorg starts with mga driver
> 
> Kernel 3.0.57-1.el6.elrepo.x86_64 (from elrepo.org - with XEN_DOM0 support)
> - "CONFIG_DRM_MGAG200" does not exist.
> - Xorg starts with mga driver
> 
> Kernel 3.7.1-3.el6xen.x86_64 (from here:
> https://www.crc.id.au/xen-on-rhel6-scientific-linux-6-centos-6-howto/
> [^<https://www.crc.id.au/xen-on-rhel6-scientific-linux-6-centos-6-howto/>]
> )
> - Since "CONFIG_DRM_MGAG200 is not set", screen is fast, but with 640x480
> resolution.
> - Xorg does not start. "Failed to activate core devices".
> 
> Kernel 3.7.1-1.el6.elrepo.x86_64 (My favorite kernel - from elrepo.org)
> - "CONFIG_DRM_MGAG200=m"
> - Native resolution
> - Screen refresh is slow
> - Xorg does not start: "Failed to activate core devices."
> 
> 
> UPDATE:
> Tested Xen 4.2.1 with Ubuntu 12.10 32-bit kernel 3.7.1 and I got the
> following results:
> 
> - Xorg with Unity works with poor performance with Xen hypervisor loaded.
> - Xorg with Unity is very nice without Xen hypervisor loaded.
> 
> - Text-based console performance is bad (as in Centos). Screen refresh is
> very slow, text scrolling also slow.
> - Text-based console performance is normal without Xen.
> 
> Exactly the same issues as in CentOS.
> 
> Content from "lspci -vv" of video card
> 
> 04:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. MGA
> G200e [Pilot] ServerEngines (SEP1) (rev 07) (prog-if 00 [VGA controller])
>         Subsystem: Intel Corporation Device 0102
>         Flags: bus master, fast devsel, latency 0, IRQ 23
>         Memory at c0000000 (32-bit, non-prefetchable) [size=16M]
>         Memory at c1810000 (32-bit, non-prefetchable) [size=16K]
>         Memory at c1000000 (32-bit, non-prefetchable) [size=8M]
>         Expansion ROM at c1800000 [disabled] [size=64K]
>         Capabilities: [dc] Power Management version 2
>         Capabilities: [e4] Express Legacy Endpoint, MSI 00
>         Capabilities: [54] MSI: Enable- Count=1/1 Maskable- 64bit-
>         Kernel driver in use: mgag200
>         Kernel modules: mgag200
> 
> 
> Thanks and sorry for the [very] bad english.

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