Ah. Thanks.It's units of 192 bit words, not straight bytes.
/proc/cpuinfo says Model: Raspberry Pi 5 Model B Rev 1.0, so I guess C1? That's unfortunate. I'll see if I can somehow split GL rendering into multiple viewports targeting the same GBM buffer, which from what I can tell fully supports width/heights larger than 4096. That way I can use the planes without downscaling and thus reducing LBM size to 0 (I think?). Thanks for the quick response!I'm suspecting you're running on BCM2712C1.
If you check SCALER6_LBM_SIZE on a D0 chip you'll get 0x00000400, or 1024 words. Various things were trimmed to reduce silicon area between C1 and D0, and sadly LBM was one of them.
Understood.The driver uses the lower value for both C1 and D0 as having it work on one and fail on the other would be far more awkward to debug.
Statistics: Posted by dividuum — Wed Jan 21, 2026 6:36 pm