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Re: [Qemu-devel] [PATCH v5 1/4] hw/display: add ramfb, a simple boot fra

From: Laszlo Ersek
Subject: Re: [Qemu-devel] [PATCH v5 1/4] hw/display: add ramfb, a simple boot framebuffer living in guest ram
Date: Fri, 15 Jun 2018 18:45:59 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0

On 06/13/18 14:29, Gerd Hoffmann wrote:
> The boot framebuffer is expected to be configured by the firmware, so it
> uses fw_cfg as interface.  Initialization goes as follows:
>   (1) Check whenever etc/ramfb is present.
>   (2) Allocate framebuffer from RAM.
>   (3) Fill struct RAMFBCfg, write it to etc/ramfb.
> Done.  You can write stuff to the framebuffer now, and it should appear
> automagically on the screen.
> Note that this isn't very efficient because it does a full display
> update on each refresh.  No dirty tracking.  Dirty tracking would have
> to be active for the whole ram slot, so that wouldn't be very efficient
> either.  For a boot display which is active for a short time only this
> isn't a big deal.  As permanent guest display something better should be
> used (if possible).
> This is the ramfb core code.  Some windup is needed for display devices
> which want have a ramfb boot display.
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  include/hw/display/ramfb.h |  9 +++++
>  hw/display/ramfb.c         | 95 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  hw/display/Makefile.objs   |  2 +
>  3 files changed, 106 insertions(+)
>  create mode 100644 include/hw/display/ramfb.h
>  create mode 100644 hw/display/ramfb.c

I tested this on KVM, built from Gerd's sirius/ramfb branch @ 778450b87275. 
Works fine with Gerd's corresponding edk2 QemuRamfbDxe driver (already merged):

  [edk2] [PATCH v3 0/4] Add QemuRamfbDxe driver

It also works fine with Ard's efifb patches:

  [PATCH 0/2] efi: add support for cacheable efifb mappings

So, for this patch (not the series):

Tested-by: Laszlo Ersek <address@hidden>


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