On 07/30/2015 10:34 AM, Javier Martinez Canillas wrote:
Hello Andrei,

This series adds support for Eric Anholt's v4.1 kernel, that has support
for the vc4 DRM/KMS driver. Which is the new open source graphics driver
stack for the Raspberry Pi to be used instead of the userland driver.

We are using it in the Tizen port to RPI2 [0] and are trying to push all
the patches back to the tizen-distro and meta-raspberrypi OE layers so
I'm posting these patches to get your feedback.

The v4.1 kernel is under heavy development so is a work-in-progress and
should not be used in production. That's why a default preference of -1
is set and the kernel only is enabled if the "vc4-gfx" feature is added
to the DISTRO_FEATURES variable.

But even when it's still a development kernel, having the recipe in the
meta-raspberrypi will allow people to test it. The patches are for:

Patch 1/5 makes optional to add the kgdboc kernel command line parameter

Patch 2/5 allows to set the mask_gpu_interrupt0 option in config.txt

Patch 3/5 changes the partition layout to add more space for boot files

Patch 4/5 adds a recipe for the 4.1 and some patches to make it stable

Patch 5/5 switchs the default providers according to the gfx stack used

One problem I found is that the latest RPI kernels changed the path for
the DT overlays after commit 739c586c8757 ("BCM270X_DT: Move the overlays
into a subdirectory, adding the README") [1] so the kernel fails to build
with the default KERNEL_DEVICETREE. I tried to change get_dts() function
logic to take this into account but found that it would had been a more
intrusive change and KERNEL_DEVICETREE will have to be changed anyways
once the recipes for the other kernels are updated to the latest HEAD so
for now I just define the following on local.conf to make it build:
As long as we bump SRCREV for 3.18 kernel as well, I see no problem. Since then the KERNEL_DEVICETREE default value can look the same in all situations (both 3.18 and 4.x can handle the new structure and we get no compatibility issues) and for older kernels (3.12 and 3.14) it doesn't matter since they don't have native device tree support and will turn device tree support off by default.


KERNEL_DEVICETREE = " \
     bcm2708-rpi-b.dtb \
     bcm2708-rpi-b-plus.dtb \
     bcm2709-rpi-2-b.dtb \
     \
     overlays/hifiberry-amp-overlay.dtb \
     overlays/hifiberry-dac-overlay.dtb \
     overlays/hifiberry-dacplus-overlay.dtb \
     overlays/hifiberry-digi-overlay.dtb \
     overlays/iqaudio-dac-overlay.dtb \
     overlays/iqaudio-dacplus-overlay.dtb \
     overlays/lirc-rpi-overlay.dtb \
     overlays/pps-gpio-overlay.dtb \
     overlays/w1-gpio-overlay.dtb \
     overlays/w1-gpio-pullup-overlay.dtb \
     "

[0]: http://blogs.s-osg.org/tizen-rpi2-now-supporting-3d-acceleration/
[1]: https://github.com/raspberrypi/linux/commit/739c586c8757

Best regards,
---
Javier Martinez Canillas
Open Source Group
Samsung Research America


Derek Foreman (4):
   rpi-config: Allow to mask GPU irqs
   sdcard_image-rpi.bbclass: Allocate more space for boot partition
   linux-raspberrypi: Add a 4.1 linux kernel with vc4 support
   rpi-default-providers: Switch providers according to used gfx stack

Mauro Carvalho Chehab (1):
   linux-raspberrypi.inc: Make kgdboc kernel param optional

  README                                             |  38 +++++--
  classes/sdcard_image-rpi.bbclass                   |   6 +-
  conf/machine/include/rpi-default-providers.inc     |   8 +-
  conf/machine/include/rpi-default-versions.inc      |   2 +-
  recipes-bsp/bootfiles/rpi-config_git.bb            |   6 ++
  recipes-kernel/linux/linux-raspberrypi.inc         |   5 +-
  ..._defconfig-Enable-config-options-for-vc4-.patch |  48 +++++++++
  ...-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch |  85 +++++++++++++++
  .../0003-drm-vc4-Use-the-fbdev_cma-helpers.patch   | 115 +++++++++++++++++++++
  .../0004-drm-vc4-Allow-vblank-to-be-disabled.patch |  26 +++++
  .../0005-drm-vc4-Disable-KMS-operations.patch      |  95 +++++++++++++++++
  recipes-kernel/linux/linux-raspberrypi_4.1.bb      |  16 +++
  12 files changed, 433 insertions(+), 17 deletions(-)
  create mode 100644 
recipes-kernel/linux/linux-raspberrypi/0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch
  create mode 100644 
recipes-kernel/linux/linux-raspberrypi/0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch
  create mode 100644 
recipes-kernel/linux/linux-raspberrypi/0003-drm-vc4-Use-the-fbdev_cma-helpers.patch
  create mode 100644 
recipes-kernel/linux/linux-raspberrypi/0004-drm-vc4-Allow-vblank-to-be-disabled.patch
  create mode 100644 
recipes-kernel/linux/linux-raspberrypi/0005-drm-vc4-Disable-KMS-operations.patch
  create mode 100644 recipes-kernel/linux/linux-raspberrypi_4.1.bb


Nice and interesting changes, but you really should sync this with Alex Lennon as well since he currently are working with integrating 4.1 into meta-raspberrypi. An other opinion is that you should start by trying to integrate relevant kernel changes both from 'git://github.com/anholt/linux.git;protocol=git;branch=vc4-kms-v3d-rpi2' and the integration patches into the currently used upstream (https://github.com/raspberrypi/linux) and I also think it's a good idea to ensure that the new code is added within kernel config options so it's easy to enable/disable the vc4 support. Then at least I think this more easily can be integrated in meta-raspberrypi.

BR,
Petter
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