Couldn't create buffer of size 3840 MB on GPU 0
Trying to run a Vega 56 on XMR on arch linux and I get this error (it won't hash)
```
 _ __   __ _ _ __   ___  _ __ ___ (_)_ __   ___ _ __
| '_ \ / _` | '_ \ / _ \| '_ ` _ \| | '_ \ / _ \ '__|
| | | | (_| | | | | (_) | | | | | | | | | |  __/ |
|_| |_|\__,_|_| |_|\___/|_| |_| |_|_|_| |_|\___|_|

Version 1.5.2
2019-07-20 12:48:18: Started EthMan server on port 3333 without a password (read-only mode).
2019-07-20 12:48:18: Started web interface on port 9090 without a password.
Single device detected
GPU 0 PCI 03:00.0, Platform: OpenCL, Name: Radeon RX Vega (gfx900), 8176 MB available
----------------CryptoNightR:---------------
Currency: Monero
Wallet: XXXX
Rig name: rig1
Email: XXX
Hashrate threshold to restart miner is not set
Added pool: xmr-us-east1.nanopool.org:14433
Added pool: xmr-us-west1.nanopool.org:14433
Auto pool sorting is disabled
Using all GPU devices
-------------Common parameters:-------------
Log path: ./logs/
Log is written to file
GPU watchdog is enabled
Never calling reboot.sh (always restarting the miner in case of errors).
2019-07-20 12:48:18: Setting up algorithm: CryptoNightR
2019-07-20 12:48:20: Connecting to pools...
2019-07-20 12:48:20: Connected to pool: xmr-us-east1.nanopool.org:14433 | ping: 256 ms.
2019-07-20 12:48:20: New job from xmr-us-east1.nanopool.org:14433 | share difficulty = 120001
Monero - Total speed: 0.000 H/s, Total shares: 0 Rejected: 0, Time: 00:01
GPU0 t=60°C fan 20% power 101.00W. Total power: 101.00W
2019-07-20 12:48:21: Couldn't create buffer of size 3840 MB on GPU 0
2019-07-20 12:48:21: Couldn't create buffer of size 3648 MB on GPU 0
```

I tried looking up the amdgpu driver for increasing buffer sizes on the module params, but not sure if y'all already knew the solution to this.

Kernel: `5.1.16-arch1-1-ARCH #1 SMP PREEMPT Wed Jul 3 20:23:07 UTC 2019 x86_64 GNU/Linux`

clinfo: 
```
ICD loader properties
  ICD loader Name                                 OpenCL ICD Loader
  ICD loader Vendor                               OCL Icd free software
  ICD loader Version                              2.2.12
  ICD loader Profile                              OpenCL 2.2
```