Date:	Tue, 02 Aug 2016 15:34:21 +0300
From:	Jani Nikula <jani.nikula@...ux.intel.com>
To:	Ville Syrjälä <ville.syrjala@...ux.intel.com>,
	Baole Ni <baolex.ni@...el.com>
Cc:	daniel.vetter@...el.com, airlied@...ux.ie,
	kyungmin.park@...sung.com, kgene@...nel.org,
	k.kozlowski@...sung.com, dougthompson@...ssion.com, bp@...en8.de,
	wuninsu@...il.com, chuansheng.liu@...el.com,
	intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org, treding@...dia.com
Subject: Re: [Intel-gfx] [PATCH 0197/1285] Replace numeric parameter like 0444 with macro

On Tue, 02 Aug 2016, Ville Syrjälä <ville.syrjala@...ux.intel.com> wrote:
> On Tue, Aug 02, 2016 at 06:48:47PM +0800, Baole Ni wrote:
>> I find that the developers often just specified the numeric value
>> when calling a macro which is defined with a parameter for access permission.
>> As we know, these numeric value for access permission have had the corresponding macro,
>> and that using macro can improve the robustness and readability of the code,
>> thus, I suggest replacing the numeric parameter with the macro.
>> 
>> Signed-off-by: Chuansheng Liu <chuansheng.liu@...el.com>
>> Signed-off-by: Baole Ni <baolex.ni@...el.com>
>> ---
>>  drivers/gpu/drm/i915/i915_params.c | 64 +++++++++++++++++++-------------------
>>  1 file changed, 32 insertions(+), 32 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
>> index 1779f02..7184e06 100644
>> --- a/drivers/gpu/drm/i915/i915_params.c
>> +++ b/drivers/gpu/drm/i915/i915_params.c
>> @@ -60,22 +60,22 @@ struct i915_params i915 __read_mostly = {
>>  	.inject_load_failure = 0,
>>  };
>>  
>> -module_param_named(modeset, i915.modeset, int, 0400);
>> +module_param_named(modeset, i915.modeset, int, S_IRUSR);
>
> At least I can't read those macros. Octal is much clearer IMO.

Besides I think we should consider making most if not all of these
parameters group/other readable. Which would then potentially become
S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH instead of just 0644.

BR,
Jani.

>
>>  MODULE_PARM_DESC(modeset,
>>  	"Use kernel modesetting [KMS] (0=disable, "
>>  	"1=on, -1=force vga console preference [default])");
>>  
>> -module_param_named_unsafe(panel_ignore_lid, i915.panel_ignore_lid, int, 0600);
>> +module_param_named_unsafe(panel_ignore_lid, i915.panel_ignore_lid, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(panel_ignore_lid,
>>  	"Override lid status (0=autodetect, 1=autodetect disabled [default], "
>>  	"-1=force lid closed, -2=force lid open)");
>>  
>> -module_param_named_unsafe(semaphores, i915.semaphores, int, 0400);
>> +module_param_named_unsafe(semaphores, i915.semaphores, int, S_IRUSR);
>>  MODULE_PARM_DESC(semaphores,
>>  	"Use semaphores for inter-ring sync "
>>  	"(default: -1 (use per-chip defaults))");
>>  
>> -module_param_named_unsafe(enable_rc6, i915.enable_rc6, int, 0400);
>> +module_param_named_unsafe(enable_rc6, i915.enable_rc6, int, S_IRUSR);
>>  MODULE_PARM_DESC(enable_rc6,
>>  	"Enable power-saving render C-state 6. "
>>  	"Different stages can be selected via bitmask values "
>> @@ -83,82 +83,82 @@ MODULE_PARM_DESC(enable_rc6,
>>  	"For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. "
>>  	"default: -1 (use per-chip default)");
>>  
>> -module_param_named_unsafe(enable_dc, i915.enable_dc, int, 0400);
>> +module_param_named_unsafe(enable_dc, i915.enable_dc, int, S_IRUSR);
>>  MODULE_PARM_DESC(enable_dc,
>>  	"Enable power-saving display C-states. "
>>  	"(-1=auto [default]; 0=disable; 1=up to DC5; 2=up to DC6)");
>>  
>> -module_param_named_unsafe(enable_fbc, i915.enable_fbc, int, 0600);
>> +module_param_named_unsafe(enable_fbc, i915.enable_fbc, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(enable_fbc,
>>  	"Enable frame buffer compression for power savings "
>>  	"(default: -1 (use per-chip default))");
>>  
>> -module_param_named_unsafe(lvds_channel_mode, i915.lvds_channel_mode, int, 0400);
>> +module_param_named_unsafe(lvds_channel_mode, i915.lvds_channel_mode, int, S_IRUSR);
>>  MODULE_PARM_DESC(lvds_channel_mode,
>>  	 "Specify LVDS channel mode "
>>  	 "(0=probe BIOS [default], 1=single-channel, 2=dual-channel)");
>>  
>> -module_param_named_unsafe(lvds_use_ssc, i915.panel_use_ssc, int, 0600);
>> +module_param_named_unsafe(lvds_use_ssc, i915.panel_use_ssc, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(lvds_use_ssc,
>>  	"Use Spread Spectrum Clock with panels [LVDS/eDP] "
>>  	"(default: auto from VBT)");
>>  
>> -module_param_named_unsafe(vbt_sdvo_panel_type, i915.vbt_sdvo_panel_type, int, 0400);
>> +module_param_named_unsafe(vbt_sdvo_panel_type, i915.vbt_sdvo_panel_type, int, S_IRUSR);
>>  MODULE_PARM_DESC(vbt_sdvo_panel_type,
>>  	"Override/Ignore selection of SDVO panel mode in the VBT "
>>  	"(-2=ignore, -1=auto [default], index in VBT BIOS table)");
>>  
>> -module_param_named_unsafe(reset, i915.reset, bool, 0600);
>> +module_param_named_unsafe(reset, i915.reset, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(reset, "Attempt GPU resets (default: true)");
>>  
>> -module_param_named_unsafe(enable_hangcheck, i915.enable_hangcheck, bool, 0644);
>> +module_param_named_unsafe(enable_hangcheck, i915.enable_hangcheck, bool, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
>>  MODULE_PARM_DESC(enable_hangcheck,
>>  	"Periodically check GPU activity for detecting hangs. "
>>  	"WARNING: Disabling this can cause system wide hangs. "
>>  	"(default: true)");
>>  
>> -module_param_named_unsafe(enable_ppgtt, i915.enable_ppgtt, int, 0400);
>> +module_param_named_unsafe(enable_ppgtt, i915.enable_ppgtt, int, S_IRUSR);
>>  MODULE_PARM_DESC(enable_ppgtt,
>>  	"Override PPGTT usage. "
>>  	"(-1=auto [default], 0=disabled, 1=aliasing, 2=full, 3=full with extended address space)");
>>  
>> -module_param_named_unsafe(enable_execlists, i915.enable_execlists, int, 0400);
>> +module_param_named_unsafe(enable_execlists, i915.enable_execlists, int, S_IRUSR);
>>  MODULE_PARM_DESC(enable_execlists,
>>  	"Override execlists usage. "
>>  	"(-1=auto [default], 0=disabled, 1=enabled)");
>>  
>> -module_param_named_unsafe(enable_psr, i915.enable_psr, int, 0600);
>> +module_param_named_unsafe(enable_psr, i915.enable_psr, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(enable_psr, "Enable PSR "
>>  		 "(0=disabled, 1=enabled - link mode chosen per-platform, 2=force link-standby mode, 3=force link-off mode) "
>>  		 "Default: -1 (use per-chip default)");
>>  
>> -module_param_named_unsafe(preliminary_hw_support, i915.preliminary_hw_support, int, 0400);
>> +module_param_named_unsafe(preliminary_hw_support, i915.preliminary_hw_support, int, S_IRUSR);
>>  MODULE_PARM_DESC(preliminary_hw_support,
>>  	"Enable preliminary hardware support.");
>>  
>> -module_param_named_unsafe(disable_power_well, i915.disable_power_well, int, 0400);
>> +module_param_named_unsafe(disable_power_well, i915.disable_power_well, int, S_IRUSR);
>>  MODULE_PARM_DESC(disable_power_well,
>>  	"Disable display power wells when possible "
>>  	"(-1=auto [default], 0=power wells always on, 1=power wells disabled when possible)");
>>  
>> -module_param_named_unsafe(enable_ips, i915.enable_ips, int, 0600);
>> +module_param_named_unsafe(enable_ips, i915.enable_ips, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(enable_ips, "Enable IPS (default: true)");
>>  
>> -module_param_named(fastboot, i915.fastboot, bool, 0600);
>> +module_param_named(fastboot, i915.fastboot, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(fastboot,
>>  	"Try to skip unnecessary mode sets at boot time (default: false)");
>>  
>> -module_param_named_unsafe(prefault_disable, i915.prefault_disable, bool, 0600);
>> +module_param_named_unsafe(prefault_disable, i915.prefault_disable, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(prefault_disable,
>>  	"Disable page prefaulting for pread/pwrite/reloc (default:false). "
>>  	"For developers only.");
>>  
>> -module_param_named_unsafe(load_detect_test, i915.load_detect_test, bool, 0600);
>> +module_param_named_unsafe(load_detect_test, i915.load_detect_test, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(load_detect_test,
>>  	"Force-enable the VGA load detect code for testing (default:false). "
>>  	"For developers only.");
>>  
>> -module_param_named_unsafe(invert_brightness, i915.invert_brightness, int, 0600);
>> +module_param_named_unsafe(invert_brightness, i915.invert_brightness, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(invert_brightness,
>>  	"Invert backlight brightness "
>>  	"(-1 force normal, 0 machine defaults, 1 force inversion), please "
>> @@ -166,47 +166,47 @@ MODULE_PARM_DESC(invert_brightness,
>>  	"to dri-devel@...ts.freedesktop.org, if your machine needs it. "
>>  	"It will then be included in an upcoming module version.");
>>  
>> -module_param_named(disable_display, i915.disable_display, bool, 0400);
>> +module_param_named(disable_display, i915.disable_display, bool, S_IRUSR);
>>  MODULE_PARM_DESC(disable_display, "Disable display (default: false)");
>>  
>> -module_param_named_unsafe(enable_cmd_parser, i915.enable_cmd_parser, int, 0600);
>> +module_param_named_unsafe(enable_cmd_parser, i915.enable_cmd_parser, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(enable_cmd_parser,
>>  		 "Enable command parsing (1=enabled [default], 0=disabled)");
>>  
>> -module_param_named_unsafe(use_mmio_flip, i915.use_mmio_flip, int, 0600);
>> +module_param_named_unsafe(use_mmio_flip, i915.use_mmio_flip, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(use_mmio_flip,
>>  		 "use MMIO flips (-1=never, 0=driver discretion [default], 1=always)");
>>  
>> -module_param_named(mmio_debug, i915.mmio_debug, int, 0600);
>> +module_param_named(mmio_debug, i915.mmio_debug, int, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(mmio_debug,
>>  	"Enable the MMIO debug code for the first N failures (default: off). "
>>  	"This may negatively affect performance.");
>>  
>> -module_param_named(verbose_state_checks, i915.verbose_state_checks, bool, 0600);
>> +module_param_named(verbose_state_checks, i915.verbose_state_checks, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(verbose_state_checks,
>>  	"Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions.");
>>  
>> -module_param_named_unsafe(nuclear_pageflip, i915.nuclear_pageflip, bool, 0600);
>> +module_param_named_unsafe(nuclear_pageflip, i915.nuclear_pageflip, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(nuclear_pageflip,
>>  		 "Force atomic modeset functionality; asynchronous mode is not yet supported. (default: false).");
>>  
>>  /* WA to get away with the default setting in VBT for early platforms.Will be removed */
>> -module_param_named_unsafe(edp_vswing, i915.edp_vswing, int, 0400);
>> +module_param_named_unsafe(edp_vswing, i915.edp_vswing, int, S_IRUSR);
>>  MODULE_PARM_DESC(edp_vswing,
>>  		 "Ignore/Override vswing pre-emph table selection from VBT "
>>  		 "(0=use value from vbt [default], 1=low power swing(200mV),"
>>  		 "2=default swing(400mV))");
>>  
>> -module_param_named_unsafe(enable_guc_submission, i915.enable_guc_submission, bool, 0400);
>> +module_param_named_unsafe(enable_guc_submission, i915.enable_guc_submission, bool, S_IRUSR);
>>  MODULE_PARM_DESC(enable_guc_submission, "Enable GuC submission (default:false)");
>>  
>> -module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
>> +module_param_named(guc_log_level, i915.guc_log_level, int, S_IRUSR);
>>  MODULE_PARM_DESC(guc_log_level,
>>  	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
>>  
>> -module_param_named_unsafe(enable_dp_mst, i915.enable_dp_mst, bool, 0600);
>> +module_param_named_unsafe(enable_dp_mst, i915.enable_dp_mst, bool, S_IRUSR | S_IWUSR);
>>  MODULE_PARM_DESC(enable_dp_mst,
>>  	"Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true)");
>> -module_param_named_unsafe(inject_load_failure, i915.inject_load_failure, uint, 0400);
>> +module_param_named_unsafe(inject_load_failure, i915.inject_load_failure, uint, S_IRUSR);
>>  MODULE_PARM_DESC(inject_load_failure,
>>  	"Force an error after a number of failure check points (0:disabled (default), N:force failure at the Nth failure check point)");
>> -- 
>> 2.9.2
>> 
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@...ts.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center

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