alistair23-linux/drivers/gpu/drm/Kconfig
Oleksandr Andrushchenko c575b7eeb8 drm/xen-front: Add support for Xen PV display frontend
Add support for Xen para-virtualized frontend display driver.
Accompanying backend [1] is implemented as a user-space application
and its helper library [2], capable of running as a Weston client
or DRM master.
Configuration of both backend and frontend is done via
Xen guest domain configuration options [3].

Driver limitations:
 1. Only primary plane without additional properties is supported.
 2. Only one video mode supported which resolution is configured
    via XenStore.
 3. All CRTCs operate at fixed frequency of 60Hz.

1. Implement Xen bus state machine for the frontend driver according to
the state diagram and recovery flow from display para-virtualized
protocol: xen/interface/io/displif.h.

2. Read configuration values from Xen store according
to xen/interface/io/displif.h protocol:
  - read connector(s) configuration
  - read buffer allocation mode (backend/frontend)

3. Handle Xen event channels:
  - create for all configured connectors and publish
    corresponding ring references and event channels in Xen store,
    so backend can connect
  - implement event channels interrupt handlers
  - create and destroy event channels with respect to Xen bus state

4. Implement shared buffer handling according to the
para-virtualized display device protocol at xen/interface/io/displif.h:
  - handle page directories according to displif protocol:
    - allocate and share page directories
    - grant references to the required set of pages for the
      page directory
  - allocate xen balllooned pages via Xen balloon driver
    with alloc_xenballooned_pages/free_xenballooned_pages
  - grant references to the required set of pages for the
    shared buffer itself
  - implement pages map/unmap for the buffers allocated by the
    backend (gnttab_map_refs/gnttab_unmap_refs)

5. Implement kernel modesetiing/connector handling using
DRM simple KMS helper pipeline:

- implement KMS part of the driver with the help of DRM
  simple pipepline helper which is possible due to the fact
  that the para-virtualized driver only supports a single
  (primary) plane:
  - initialize connectors according to XenStore configuration
  - handle frame done events from the backend
  - create and destroy frame buffers and propagate those
    to the backend
  - propagate set/reset mode configuration to the backend on display
    enable/disable callbacks
  - send page flip request to the backend and implement logic for
    reporting backend IO errors on prepare fb callback

- implement virtual connector handling:
  - support only pixel formats suitable for single plane modes
  - make sure the connector is always connected
  - support a single video mode as per para-virtualized driver
    configuration

6. Implement GEM handling depending on driver mode of operation:
depending on the requirements for the para-virtualized environment,
namely requirements dictated by the accompanying DRM/(v)GPU drivers
running in both host and guest environments, number of operating
modes of para-virtualized display driver are supported:
 - display buffers can be allocated by either
   frontend driver or backend
 - display buffers can be allocated to be contiguous
   in memory or not

Note! Frontend driver itself has no dependency on contiguous memory for
its operation.

6.1. Buffers allocated by the frontend driver.

The below modes of operation are configured at compile-time via
frontend driver's kernel configuration.

6.1.1. Front driver configured to use GEM CMA helpers
     This use-case is useful when used with accompanying DRM/vGPU driver
     in guest domain which was designed to only work with contiguous
     buffers, e.g. DRM driver based on GEM CMA helpers: such drivers can
     only import contiguous PRIME buffers, thus requiring frontend driver
     to provide such. In order to implement this mode of operation
     para-virtualized frontend driver can be configured to use
     GEM CMA helpers.

6.1.2. Front driver doesn't use GEM CMA
     If accompanying drivers can cope with non-contiguous memory then, to
     lower pressure on CMA subsystem of the kernel, driver can allocate
     buffers from system memory.

Note! If used with accompanying DRM/(v)GPU drivers this mode of operation
may require IOMMU support on the platform, so accompanying DRM/vGPU
hardware can still reach display buffer memory while importing PRIME
buffers from the frontend driver.

6.2. Buffers allocated by the backend

This mode of operation is run-time configured via guest domain
configuration through XenStore entries.

For systems which do not provide IOMMU support, but having specific
requirements for display buffers it is possible to allocate such buffers
at backend side and share those with the frontend.
For example, if host domain is 1:1 mapped and has DRM/GPU hardware
expecting physically contiguous memory, this allows implementing
zero-copying use-cases.

Note, while using this scenario the following should be considered:
  a) If guest domain dies then pages/grants received from the backend
     cannot be claimed back
  b) Misbehaving guest may send too many requests to the
     backend exhausting its grant references and memory
     (consider this from security POV).

Note! Configuration options 1.1 (contiguous display buffers) and 2
(backend allocated buffers) are not supported at the same time.

7. Handle communication with the backend:
 - send requests and wait for the responses according
   to the displif protocol
 - serialize access to the communication channel
 - time-out used for backend communication is set to 3000 ms
 - manage display buffers shared with the backend

[1] https://github.com/xen-troops/displ_be
[2] https://github.com/xen-troops/libxenbe
[3] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/man/xl.cfg.pod.5.in;h=a699367779e2ae1212ff8f638eff0206ec1a1cc9;hb=refs/heads/master#l1257

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180403112317.28751-2-andr2000@gmail.com
2018-04-03 14:41:48 +03:00

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#
# Drm device configuration
#
# This driver provides support for the
# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
#
menuconfig DRM
tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)"
depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && HAS_DMA
select DRM_PANEL_ORIENTATION_QUIRKS
select HDMI
select FB_CMDLINE
select I2C
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
select SYNC_FILE
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
the module that's right for your graphics card from the list below.
These modules provide support for synchronization, security, and
DMA transfers. Please see <http://dri.sourceforge.net/> for more
details. You should also select and configure AGP
(/dev/agpgart) support if it is available for your platform.
config DRM_MIPI_DSI
bool
depends on DRM
config DRM_DP_AUX_CHARDEV
bool "DRM DP AUX Interface"
depends on DRM
help
Choose this option to enable a /dev/drm_dp_auxN node that allows to
read and write values to arbitrary DPCD registers on the DP aux
channel.
config DRM_DEBUG_MM
bool "Insert extra checks and debug info into the DRM range managers"
default n
depends on DRM=y
depends on STACKTRACE_SUPPORT
select STACKDEPOT
help
Enable allocation tracking of memory manager and leak detection on
shutdown.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_DEBUG_MM_SELFTEST
tristate "kselftests for DRM range manager (struct drm_mm)"
depends on DRM
depends on DEBUG_KERNEL
select PRIME_NUMBERS
select DRM_LIB_RANDOM
default n
help
This option provides a kernel module that can be used to test
the DRM range manager (drm_mm) and its API. This option is not
useful for distributions or general kernels, but only for kernel
developers working on DRM and associated drivers.
If in doubt, say "N".
config DRM_KMS_HELPER
tristate
depends on DRM
help
CRTC helpers for KMS drivers.
config DRM_KMS_FB_HELPER
bool
depends on DRM_KMS_HELPER
select FB
select FRAMEBUFFER_CONSOLE if !EXPERT
select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE
select FB_SYS_FOPS
select FB_SYS_FILLRECT
select FB_SYS_COPYAREA
select FB_SYS_IMAGEBLIT
select FB_CFB_FILLRECT
select FB_CFB_COPYAREA
select FB_CFB_IMAGEBLIT
select FB_DEFERRED_IO
help
FBDEV helpers for KMS drivers.
config DRM_FBDEV_EMULATION
bool "Enable legacy fbdev support for your modesetting driver"
depends on DRM
select DRM_KMS_HELPER
select DRM_KMS_FB_HELPER
default y
help
Choose this option if you have a need for the legacy fbdev
support. Note that this support also provides the linux console
support on top of your modesetting driver.
If in doubt, say "Y".
config DRM_FBDEV_OVERALLOC
int "Overallocation of the fbdev buffer"
depends on DRM_FBDEV_EMULATION
default 100
help
Defines the fbdev buffer overallocation in percent. Default
is 100. Typical values for double buffering will be 200,
triple buffering 300.
config DRM_LOAD_EDID_FIRMWARE
bool "Allow to specify an EDID data set instead of probing for it"
depends on DRM
help
Say Y here, if you want to use EDID data to be loaded from the
/lib/firmware directory or one of the provided built-in
data sets. This may be necessary, if the graphics adapter or
monitor are unable to provide appropriate EDID data. Since this
feature is provided as a workaround for broken hardware, the
default case is N. Details and instructions how to build your own
EDID data are given in Documentation/EDID/HOWTO.txt.
config DRM_TTM
tristate
depends on DRM && MMU
help
GPU memory management subsystem for devices with multiple
GPU memory types. Will be enabled automatically if a device driver
uses it.
config DRM_GEM_CMA_HELPER
bool
depends on DRM
help
Choose this if you need the GEM CMA helper functions
config DRM_KMS_CMA_HELPER
bool
depends on DRM
select DRM_GEM_CMA_HELPER
select DRM_KMS_FB_HELPER
select FB_SYS_FILLRECT
select FB_SYS_COPYAREA
select FB_SYS_IMAGEBLIT
help
Choose this if you need the KMS CMA helper functions
config DRM_VM
bool
depends on DRM && MMU
config DRM_SCHED
tristate
depends on DRM
source "drivers/gpu/drm/i2c/Kconfig"
source "drivers/gpu/drm/arm/Kconfig"
config DRM_RADEON
tristate "ATI Radeon"
depends on DRM && PCI && MMU
select FW_LOADER
select DRM_KMS_HELPER
select DRM_TTM
select POWER_SUPPLY
select HWMON
select BACKLIGHT_CLASS_DEVICE
select BACKLIGHT_LCD_SUPPORT
select INTERVAL_TREE
help
Choose this option if you have an ATI Radeon graphics card. There
are both PCI and AGP versions. You don't need to choose this to
run the Radeon in plain VGA mode.
If M is selected, the module will be called radeon.
source "drivers/gpu/drm/radeon/Kconfig"
config DRM_AMDGPU
tristate "AMD GPU"
depends on DRM && PCI && MMU
select FW_LOADER
select DRM_KMS_HELPER
select DRM_SCHED
select DRM_TTM
select POWER_SUPPLY
select HWMON
select BACKLIGHT_CLASS_DEVICE
select BACKLIGHT_LCD_SUPPORT
select INTERVAL_TREE
select CHASH
help
Choose this option if you have a recent AMD Radeon graphics card.
If M is selected, the module will be called amdgpu.
source "drivers/gpu/drm/amd/amdgpu/Kconfig"
source "drivers/gpu/drm/amd/lib/Kconfig"
source "drivers/gpu/drm/nouveau/Kconfig"
source "drivers/gpu/drm/i915/Kconfig"
config DRM_VGEM
tristate "Virtual GEM provider"
depends on DRM
help
Choose this option to get a virtual graphics memory manager,
as used by Mesa's software renderer for enhanced performance.
If M is selected the module will be called vgem.
source "drivers/gpu/drm/exynos/Kconfig"
source "drivers/gpu/drm/rockchip/Kconfig"
source "drivers/gpu/drm/vmwgfx/Kconfig"
source "drivers/gpu/drm/gma500/Kconfig"
source "drivers/gpu/drm/udl/Kconfig"
source "drivers/gpu/drm/ast/Kconfig"
source "drivers/gpu/drm/mgag200/Kconfig"
source "drivers/gpu/drm/cirrus/Kconfig"
source "drivers/gpu/drm/armada/Kconfig"
source "drivers/gpu/drm/atmel-hlcdc/Kconfig"
source "drivers/gpu/drm/rcar-du/Kconfig"
source "drivers/gpu/drm/shmobile/Kconfig"
source "drivers/gpu/drm/sun4i/Kconfig"
source "drivers/gpu/drm/omapdrm/Kconfig"
source "drivers/gpu/drm/tilcdc/Kconfig"
source "drivers/gpu/drm/qxl/Kconfig"
source "drivers/gpu/drm/bochs/Kconfig"
source "drivers/gpu/drm/virtio/Kconfig"
source "drivers/gpu/drm/msm/Kconfig"
source "drivers/gpu/drm/fsl-dcu/Kconfig"
source "drivers/gpu/drm/tegra/Kconfig"
source "drivers/gpu/drm/stm/Kconfig"
source "drivers/gpu/drm/panel/Kconfig"
source "drivers/gpu/drm/bridge/Kconfig"
source "drivers/gpu/drm/sti/Kconfig"
source "drivers/gpu/drm/amd/amdkfd/Kconfig"
source "drivers/gpu/drm/imx/Kconfig"
source "drivers/gpu/drm/vc4/Kconfig"
source "drivers/gpu/drm/etnaviv/Kconfig"
source "drivers/gpu/drm/arc/Kconfig"
source "drivers/gpu/drm/hisilicon/Kconfig"
source "drivers/gpu/drm/mediatek/Kconfig"
source "drivers/gpu/drm/zte/Kconfig"
source "drivers/gpu/drm/mxsfb/Kconfig"
source "drivers/gpu/drm/meson/Kconfig"
source "drivers/gpu/drm/tinydrm/Kconfig"
source "drivers/gpu/drm/pl111/Kconfig"
source "drivers/gpu/drm/tve200/Kconfig"
source "drivers/gpu/drm/xen/Kconfig"
# Keep legacy drivers last
menuconfig DRM_LEGACY
bool "Enable legacy drivers (DANGEROUS)"
depends on DRM && MMU
select DRM_VM
help
Enable legacy DRI1 drivers. Those drivers expose unsafe and dangerous
APIs to user-space, which can be used to circumvent access
restrictions and other security measures. For backwards compatibility
those drivers are still available, but their use is highly
inadvisable and might harm your system.
You are recommended to use the safe modeset-only drivers instead, and
perform 3D emulation in user-space.
Unless you have strong reasons to go rogue, say "N".
if DRM_LEGACY
config DRM_TDFX
tristate "3dfx Banshee/Voodoo3+"
depends on DRM && PCI
help
Choose this option if you have a 3dfx Banshee or Voodoo3 (or later),
graphics card. If M is selected, the module will be called tdfx.
config DRM_R128
tristate "ATI Rage 128"
depends on DRM && PCI
select FW_LOADER
help
Choose this option if you have an ATI Rage 128 graphics card. If M
is selected, the module will be called r128. AGP support for
this card is strongly suggested (unless you have a PCI version).
config DRM_I810
tristate "Intel I810"
# !PREEMPT because of missing ioctl locking
depends on DRM && AGP && AGP_INTEL && (!PREEMPT || BROKEN)
help
Choose this option if you have an Intel I810 graphics card. If M is
selected, the module will be called i810. AGP support is required
for this driver to work.
config DRM_MGA
tristate "Matrox g200/g400"
depends on DRM && PCI
select FW_LOADER
help
Choose this option if you have a Matrox G200, G400 or G450 graphics
card. If M is selected, the module will be called mga. AGP
support is required for this driver to work.
config DRM_SIS
tristate "SiS video cards"
depends on DRM && AGP
depends on FB_SIS || FB_SIS=n
help
Choose this option if you have a SiS 630 or compatible video
chipset. If M is selected the module will be called sis. AGP
support is required for this driver to work.
config DRM_VIA
tristate "Via unichrome video cards"
depends on DRM && PCI
help
Choose this option if you have a Via unichrome or compatible video
chipset. If M is selected the module will be called via.
config DRM_SAVAGE
tristate "Savage video cards"
depends on DRM && PCI
help
Choose this option if you have a Savage3D/4/SuperSavage/Pro/Twister
chipset. If M is selected the module will be called savage.
endif # DRM_LEGACY
# Separate option because drm_panel_orientation_quirks.c is shared with fbdev
config DRM_PANEL_ORIENTATION_QUIRKS
tristate
config DRM_LIB_RANDOM
bool
default n