Accessing MSM Frame Buffer Driver

[Rehan Hameed]

I am trying to access and update the display LUT on a Qualcomm chipset based device (Nexus 5X) and need some help on that.

I have figured out that the MSM frame buffer driver at the link below has the support for doing this:

https://android.googlesource.com/kernel/msm/+/android-msm-bullhead-3.10-marshmallow-dr/drivers/video/msm/

(the case MSMFB_SET_LUT, in the msm_fb_ioctl function is doing this).

However I am not sure what is the right interface to connect to the MSM_FB driver. Should I be able to open /dev/graphics/fb0 and do an ioctl call on it to access this functionality? (I apologize my knowledge of linux / android devcie drivers is pretty rudimentary).

Also my final code gets integrated into Android SurfaceFlinger. I am assuming SurfaceFlinger would have a direct interface to the frame buffer driver and probably doesn't need to open /dev/graphics/fb0 to access the driver. However I don't know what is the interface from SurfaceFlinger to FB driver.

Would be great to get some input on this!

I should clarify that I am running an AOSP build of Android (6.0) on a
rooted Nexus 5X.