55 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			55 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| { config, lib, ... }:
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| 
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| with lib;
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| 
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| let
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| 
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|   cfg = config.powerManagement.scsiLinkPolicy;
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| 
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|   kernel = config.boot.kernelPackages.kernel;
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| 
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|   allowedValues = [
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|     "min_power"
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|     "max_performance"
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|     "medium_power"
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|     "med_power_with_dipm"
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|   ];
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| 
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| in
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| 
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| {
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|   ###### interface
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| 
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|   options = {
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| 
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|     powerManagement.scsiLinkPolicy = mkOption {
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|       default = null;
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|       type = types.nullOr (types.enum allowedValues);
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|       description = ''
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|         SCSI link power management policy. The kernel default is
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|         "max_performance".
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|         </para><para>
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|         "med_power_with_dipm" is supported by kernel versions
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|         4.15 and newer.
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|       '';
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|     };
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| 
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|   };
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| 
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| 
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|   ###### implementation
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| 
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|   config = mkIf (cfg != null) {
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| 
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|     assertions = singleton {
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|       assertion = (cfg == "med_power_with_dipm") -> versionAtLeast kernel.version "4.15";
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|       message = "med_power_with_dipm is not supported for kernels older than 4.15";
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|     };
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| 
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|     services.udev.extraRules = ''
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|       SUBSYSTEM=="scsi_host", ACTION=="add", KERNEL=="host*", ATTR{link_power_management_policy}="${cfg}"
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|     '';
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|   };
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| 
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| }
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