Hi Heinrich, On Wed, 31 Dec 2025 at 06:44, Heinrich Schuchardt <[email protected]> wrote: > > Describe how the QEMU defconfigs can be used with an emulated GPU. > > Signed-off-by: Heinrich Schuchardt <[email protected]> > --- > doc/board/emulation/index.rst | 1 + > doc/board/emulation/video.rst | 63 +++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > create mode 100644 doc/board/emulation/video.rst
Reviewed-by: Simon Glass <[email protected]> > > diff --git a/doc/board/emulation/index.rst b/doc/board/emulation/index.rst > index f8908166276..bda2240725f 100644 > --- a/doc/board/emulation/index.rst > +++ b/doc/board/emulation/index.rst > @@ -15,6 +15,7 @@ Emulation > qemu-sbsa > qemu-x86 > qemu-xtensa > + video > > Also see > > diff --git a/doc/board/emulation/video.rst b/doc/board/emulation/video.rst > new file mode 100644 > index 00000000000..4943dcabeab > --- /dev/null > +++ b/doc/board/emulation/video.rst > @@ -0,0 +1,63 @@ > +.. SPDX-License-Identifier: GPL-2.0-or-later > + > +Emulation of a graphics adapter > +=============================== > + > +Currently QEMU's ``bochs-display`` is the only emulated GPU that U-Boot's > +generic QEMU defconfigs support. It emulates a PCIe connected graphics card PCIe-connected > +with VESA 2.0 VBE extensions. > + > +The following parameters can be specified. > + > +edid > + controls if EDID information is available. Allowable values are ``off`` > and > + ``on``. The default is on. > + > +vgamem > + specifies the display memory size. The default value is 16 MiB. > + For UHD resolution 32 MiB is required. > + > +The following configuration parameters are relevant: > + > +CONFIG_VIDEO_BOCHS > + enable support for the Bochs GPU. > + > +CONFIG_VIDEO_BOCHS_SIZE_X > + defines the display width. > + > +CONFIG_VIDEO_BOCHS_SIZE_Y > + defines isplay height. display > + > +CONFIG_VIDEO_PCI_DEFAULT_FB_SIZE > + sets the framebuffer size that QEMU can use for a device driver that is > + enabled after relocation. This should be chosed as chosen > + > + .. code-block:: > + > + CONFIG_VIDEO_PCI_DEFAULT_FB_SIZE >= > + 4 * CONFIG_VIDEO_BOCHS_SIZE_X * CONFIG_VIDEO_BOCHS_SIZE_Y > + > +Here is an example QEMU invocation for qemu-riscv64_smode_defconfig: > + > +.. code-block:: bash > + > + qemu-system-riscv64 \ > + -M virt \ > + -device bochs-display,vgamem=33554432 \ > + -serial mon:stdio \ > + -device qemu-xhci \ > + -device usb-kbd \ > + -kernel u-boot > + > +``mon:stdio`` provides a serial console. ``qemu-xhci`` a USB root hub. > +``usb-kbd`` a USB keyboard. > + > +To start QEMU without GPU emulation use parameter ``-nographic`` like in the > +following example. > + > +.. code-block:: bash > + > + qemu-system-riscv64 \ > + -M virt \ > + -nographic \ > + -kernel u-boot > -- > 2.51.0 > The Concept tree has build-qemu which handles these details. I wonder if those scripts could be put into the extra repo Tom created? Regards, Simon
