linux-toradex.git/drivers/gpu/drm/mgag200/Kconfig, branch master

PCI: Add CONFIG_MMU dependency

2025-04-23T20:40:30+00:00

It turns out that there are no platforms that have PCI but don't have an
MMU, so adding a Kconfig dependency on CONFIG_PCI simplifies build testing
kernels for those platforms a lot, and avoids a lot of inadvertent build
regressions.

Add a dependency for CONFIG_PCI and remove all the ones for PCI specific
device drivers that are currently marked not having it.

There are a few platforms that have an optional MMU, but they usually
cannot have PCI at all. The one exception is Coldfire MCF54xx, but this is
mainly for historic reasons, and anyone using those chips should really use
the MMU these days.

Link: https://lore.kernel.org/lkml/a41f1b20-a76c-43d8-8c36-f12744327a54@app.fastmail.com/
Signed-off-by: Arnd Bergmann 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Martin K. Petersen  # SCSI
Reviewed-by: Thomas Zimmermann 
Acked-by: Alex Deucher 
Link: https://patch.msgid.link/20250423202215.3315550-1-arnd@kernel.org

drm/mgag200: Run DRM default client setup

2024-09-26T07:31:28+00:00

Call drm_client_setup_with_fourcc() to run the kernel's default client
setup for DRM. Set fbdev_probe in struct drm_driver, so that the client
setup can start the common fbdev client.

v5:
- select DRM_CLIENT_SELECTION
v2:
- use drm_client_setup_with_fourcc()

Signed-off-by: Thomas Zimmermann 
Cc: Dave Airlie 
Cc: Thomas Zimmermann 
Cc: Jocelyn Falempe 
Reviewed-by: Jocelyn Falempe 
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-57-tzimmermann@suse.de

drm/mgag200: Add an option to disable Write-Combine

2024-05-21T07:38:47+00:00

Unfortunately, the G200 ioburst workaround doesn't work on some
servers like Dell poweredge XR11, XR5610, or HPE XL260. In this case
completely disabling WC is the only option to achieve low-latency.
So this adds a new Kconfig option to disable WC mapping of the G200.

Signed-off-by: Jocelyn Falempe 
Reviewed-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/20240517151050.624797-3-jfalempe@redhat.com

Revert "drm/mgag200: Add a workaround for low-latency"

2024-05-21T07:38:46+00:00

This reverts commit bfa4437fd3938ae2e186e7664b2db65bb8775670.

This workaround doesn't work reliably on all servers.
I'll replace it with an option to disable Write-Combine,
which has more impact on performance, but fix the latency
issue on all hardware.

Signed-off-by: Jocelyn Falempe 
Reviewed-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/20240517151050.624797-2-jfalempe@redhat.com

drm/mgag200: Add a workaround for low-latency

2024-02-26T15:37:51+00:00

We found a regression in v5.10 on real-time server, using the
rt-kernel and the mgag200 driver. It's some really specialized
workload, with <10us latency expectation on isolated core.
After the v5.10, the real time tasks missed their <10us latency
when something prints on the screen (fbcon or printk)

The regression has been bisected to 2 commits:
commit 0b34d58b6c32 ("drm/mgag200: Enable caching for SHMEM pages")
commit 4862ffaec523 ("drm/mgag200: Move vmap out of commit tail")

The first one changed the system memory framebuffer from Write-Combine
to the default caching.
Before the second commit, the mgag200 driver used to unmap the
framebuffer after each frame, which implicitly does a cache flush.
Both regressions are fixed by this commit, which restore WC mapping
for the framebuffer in system memory, and add a cache flush.
This is only needed on x86_64, for low-latency workload,
so the new kconfig DRM_MGAG200_IOBURST_WORKAROUND depends on
PREEMPT_RT and X86.

For more context, the whole thread can be found here [1]

Signed-off-by: Jocelyn Falempe 
Link: https://lore.kernel.org/dri-devel/20231019135655.313759-1-jfalempe@redhat.com/ # 1
Acked-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/20240208095125.377908-1-jfalempe@redhat.com

drm: Only select I2C_ALGOBIT for drivers that actually need it

2023-01-10T10:15:44+00:00

While working on a drm driver that doesn't need the i2c algobit stuff I
noticed that DRM selects this code even though only 8 drivers actually use
it. While also only some drivers use i2c, keep the select for I2C for the
next cleanup patch. Still prepare this already by also selecting I2C for
the individual drivers.

Signed-off-by: Uwe Kleine-König 
Reviewed-by: Javier Martinez Canillas 
Signed-off-by: Javier Martinez Canillas 
Link: https://patchwork.freedesktop.org/patch/msgid/20221219083627.1401627-1-u.kleine-koenig@pengutronix.de

drm/mgag200: Add support for G200 desktop cards

2020-08-03T07:43:00+00:00

This patch adds support for G200 desktop cards. We can reuse the whole
memory and modesetting code. A few PCI and DAC register values have to
be updated accordingly.

The most significant change is in the PLL setup. The driver parses the
device's BIOS to retrieve clock limits and reference clocks. With no BIOS
found, safe defaults are being used.

v2:
	* copy BIOS ROM to system memory and access with regular
	  load/store; resolves potential HW limitations
	* fix some stray whitespaces

Signed-off-by: Thomas Zimmermann 
Co-developed-by: Egbert Eich 
Signed-off-by: Egbert Eich 
Co-developed-by: Takashi Iwai 
Signed-off-by: Takashi Iwai 
Reviewed-by: Lyude Paul 
Link: https://patchwork.freedesktop.org/patch/msgid/20200730102844.10995-9-tzimmermann@suse.de

drm/mgag200: Replace VRAM helpers with SHMEM helpers

2020-05-19T07:41:34+00:00

The VRAM helpers managed the framebuffer memory for mgag200. This came
with several problems, as some MGA device require the scanout address
to be located at VRAM offset 0. It's incompatible with the page-flip
semantics of DRM's atomic modesettting. With atomic modesetting, old and
new framebuffers have to be located in VRAM at the same time. So at least
one of them has to reside at a non-0 offset.

This patch replaces VRAM helpers with SHMEM helpers. GEM SHMEM buffers
reside in system memory, and are shadow-copied into VRAM during page
flips. The shadow copy always starts at VRAM offset 0.

v2:
	* revert dev->pdev changes

Signed-off-by: Thomas Zimmermann 
Tested-by: John Donnelly 
Acked-by: Emil Velikov 
Link: https://patchwork.freedesktop.org/patch/msgid/20200515083233.32036-16-tzimmermann@suse.de

drm/mgag200: Fix Kconfig indentation

2019-11-20T16:40:32+00:00

Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
	$ sed -e 's/^        /\t/' -i */Kconfig

Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20191120133625.11478-1-krzk@kernel.org

drm/vram: fix Kconfig

2019-09-10T06:53:08+00:00

select isn't recursive, so we can't turn on DRM_TTM + DRM_TTM_HELPER
in config DRM_VRAM_HELPER, we have to select them on the vram users
instead.

Signed-off-by: Gerd Hoffmann 
Acked-by: Thomas Zimmermann 
Link: http://patchwork.freedesktop.org/patch/msgid/20190904054740.20817-8-kraxel@redhat.com