drm_hwcomposer: Add feature to search for KMS DRI card
Most modern SOCs have separate IP cores for GPU and Display Unit (KMS).
Also, there is no warranty that the KMS card will always have
/dev/dri/card0 path and GPU - /dev/dri/card1, but drm_hwcomposer should
open only KMS device. The order can depend on many factors. For example:
on the rpi4 board, it was observed that enabling the WIFI kernel module
swapping the card order. Therefore searching for the KMS card is the only
efficient solution.
The IsKMSDev function returns true when the file descriptor on the path
is successfully opened, the drmlib function is returned resources and
the target device has at least one CTRC, connector, and encoder. Also,
the patch enables finding KMS devices in the case of the absence of
the system property specification.
Signed-off-by: Matvii Zorin <matvii.zorin@globallogic.com>
Reviewed-by: Roman Stratiienko <r.stratiienko@gmail.com>
Change-Id: I8874a50188207833389fadd4815b42a80bf69240
diff --git a/include/resourcemanager.h b/include/resourcemanager.h
index 7a86828..9fefb46 100644
--- a/include/resourcemanager.h
+++ b/include/resourcemanager.h
@@ -46,6 +46,7 @@
private:
int AddDrmDevice(std::string path);
+ static bool IsKMSDev(const char *path);
int num_displays_;
std::vector<std::unique_ptr<DrmDevice>> drms_;