Hello,
In a normal use case, the VGA DDC lines are used to read EDID from the
display. On some systems where the connector is internal to the device
and the VGA display is always present, the DDC lines may not be
connected, making display detection and EDID retrieval impossible.
This patch series adds the ability to hardcode EDID in the device tree
for VGA connectors on such systems. Patch 1/4 extends the vga-connector
DT bindings with an "edid" property. Patch 2/4 is a drive-by fix for a
resource leak in the display-connector driver, and patch 3/4 implements
support for the "edid" property in the driver.
I have tested this on a Renesas Salvator-XS M3N development board. The
board has an external VGA connector, but does not conenct the DDC lines,
exhibiting the problem that this series addresses. Patch 4/4
demonstrates how to set EDID in the device tree, for the VGA monitor I
used in my test environment. It is not meant to be merged as the display
is not internal to the device in this case.
Laurent Pinchart (4):
dt-bindings: display: vga-connector: Allow hardcoding EDID
drm/bridge: display-connector: Fix I2C adapter resource leak
drm/bridge: display-connector: Support hardcoded EDID for VGA
connectors
[DNI] arm64: dts: renesas: salvator: Add overlay for Dell P1911 VGA
display
.../display/connector/vga-connector.yaml | 15 +++++++
arch/arm64/boot/dts/renesas/Makefile | 2 +
.../dts/renesas/salvator-vga-dell-p1911.dtso | 21 ++++++++++
drivers/gpu/drm/bridge/display-connector.c | 42 ++++++++++++++++---
4 files changed, 75 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/boot/dts/renesas/salvator-vga-dell-p1911.dtso
base-commit: 44d19b8a7548aa25cbc6ebd5f27e958f7142c36b
--
Regards,
Laurent Pinchart
