From: Hans Verkuil hans.verkuil@cisco.com
This patch series adds support for HDMI CEC to the vc4 drm driver. This series is based on 4.13-rc1.
Note: the first cec patch is independent of the vc4 patches and will be merged via the media subsystem for 4.14. Without that patch everything will still work, but it will attempt to retry messages twice as many times as it should.
This has been tested with the Raspberry Pi 2B and 3B. I don't have older rpi's, so I can't test those.
Many thanks to Eric Anholt for his help with this driver!
There is one open issue: when booting the rpi without an HDMI cable connected, then CEC won't work. But neither apparently does HDMI since reconnecting it will not bring back any display.
If you boot with the HDMI cable connected, then all is well and disconnecting and reconnecting the cable will do the right thing.
I don't understand what is going on here, but it does not appear to be CEC related and the same problem occurs without this patch series.
You also need to update your config.txt with this line to prevent the firmware from eating the CEC interrupts:
mask_gpu_interrupt1=0x100
Eric, I've experimented with setting hdmi_ignore_cec=1 but that simply doesn't work. Instead that disables CEC completely. With this mask_gpu_interrupt1 setting everything works perfectly. This also prevents the firmware from sending the initial Active Source CEC message so the CPU has full control over the CEC bus, as it should.
My main concern is that this is rather magical, but it is not something I have any control over.
Changes since v1:
- Merged patch 3 and 4 together as suggested by Eric. - The clock divider is now set explicitly instead of relying on the default value.
Regards,
Hans
Hans Verkuil (3): cec: be smarter about detecting the number of attempts made drm/vc4: prepare for CEC support drm/vc4: add HDMI CEC support
drivers/gpu/drm/vc4/Kconfig | 8 ++ drivers/gpu/drm/vc4/vc4_hdmi.c | 284 ++++++++++++++++++++++++++++++++++++----- drivers/gpu/drm/vc4/vc4_regs.h | 113 ++++++++++++++++ drivers/media/cec/cec-adap.c | 9 +- 4 files changed, 377 insertions(+), 37 deletions(-)