# Kernel Boot Params

## Updating Grub

To select the `AMDGPU` driver / module.

https://askubuntu.com/a/1314983

I'll add the following flags to the appropriate line in `/etc/default/grub`

```
GRUB_CMDLINE_LINUX_DEFAULT="radeon.si_support=0 radeon.cik_support=0 amdgpu.si_support=1 amdgpu.cik_support=1 amdgpu.dc=1 amdgpu.dpm=1 amdgpu.modeset=1"
```

Then run

```
sudo update-grub
```

and reboot, selecting Ubuntu 20.04 per this branch of the debugging tree.

## Rebooting

After rebooting, `OpenCL` detects the GPU! But it hangs and does not return from the call

```
sudo clinfo -l
```

The call without the `sudo` yields just the CPU and `Number of devices: 0` as before.

Here's the glorious output:

```
$ sudo clinfo -l
[sudo] password for arcologos: 
Number of platforms:				 1
  Platform Profile:				 FULL_PROFILE
  Platform Version:				 OpenCL 2.1 AMD-APP (3558.0)
  Platform Name:				 AMD Accelerated Parallel Processing
  Platform Vendor:				 Advanced Micro Devices, Inc.
  Platform Extensions:				 cl_khr_icd cl_amd_event_callback 


  Platform Name:				 AMD Accelerated Parallel Processing
Number of devices:				 1
  Device Type:					 CL_DEVICE_TYPE_GPU
  Vendor ID:					 1002h
  Board name:					 AMD Radeon (TM) R9 390 Series
  Device Topology:				 PCI[ B#3, D#0, F#0 ]
  Max compute units:				 40
  Max work items dimensions:			 3
    Max work items[0]:				 1024
    Max work items[1]:				 1024
    Max work items[2]:				 1024
  Max work group size:				 256
  Preferred vector width char:			 4
  Preferred vector width short:			 2
  Preferred vector width int:			 1
  Preferred vector width long:			 1
  Preferred vector width float:			 1
  Preferred vector width double:		 1
  Native vector width char:			 4
  Native vector width short:			 2
  Native vector width int:			 1
  Native vector width long:			 1
  Native vector width float:			 1
  Native vector width double:			 1
  Max clock frequency:				 1005Mhz
  Address bits:					 64
  Max memory allocation:			 7301444400
  Image support:				 Yes
  Max number of images read arguments:		 128
  Max number of images write arguments:		 8
  Max image 2D width:				 16384
  Max image 2D height:				 16384
  Max image 3D width:				 16384
  Max image 3D height:				 16384
  Max image 3D depth:				 8192
  Max samplers within kernel:			 26545
  Max size of kernel argument:			 1024
  Alignment (bits) of base address:		 1024
  Minimum alignment (bytes) for any datatype:	 128
  Single precision floating point capability
    Denorms:					 No
    Quiet NaNs:					 Yes
    Round to nearest even:			 Yes
    Round to zero:				 Yes
    Round to +ve and infinity:			 Yes
    IEEE754-2008 fused multiply-add:		 Yes
  Cache type:					 Read/Write
  Cache line size:				 64
  Cache size:					 16384
  Global memory size:				 8589934592
  Constant buffer size:				 7301444400
  Max number of constant args:			 8
  Local memory type:				 Scratchpad
  Local memory size:				 65536
  Max pipe arguments:				 16
  Max pipe active reservations:			 16
  Max pipe packet size:				 3006477104
  Max global variable size:			 7301444400
  Max global variable preferred total size:	 8589934592
  Max read/write image args:			 64
  Max on device events:				 1024
  Queue on device max size:			 8388608
  Max on device queues:				 1
  Queue on device preferred size:		 262144
  SVM capabilities:				 
    Coarse grain buffer:			 Yes
    Fine grain buffer:				 Yes
    Fine grain system:				 No
    Atomics:					 No
  Preferred platform atomic alignment:		 0
  Preferred global atomic alignment:		 0
  Preferred local atomic alignment:		 0
```

## Add User to Video Group

Per this response

https://github.com/RadeonOpenCompute/ROCm/issues/482#issuecomment-410551357 

I add the current user to the `video` group. I forget where I first read that this was necessary, but next also
is to try the `render` group.

```
sudo usermod -G video -a $USER

```