drm/i915: move module parameters into a struct, in a new file

With 20+ module parameters, I think referring to them via a struct
improves clarity over just having a bunch of globals. While at it, move
the parameter initialization and definitions into a new file
i915_params.c to reduce clutter in i915_drv.c.

Apart from the ill-named i915_enable_rc6, i915_enable_fbc and
i915_enable_ppgtt parameters, for which we lose the "i915_" prefix
internally, the module parameters now look the same both on the kernel
command line and in code. For example, "i915.modeset".

The downsides of the change are losing static on a couple of variables
and not having the initialization and module_param_named() right next to
each other. On the other hand, all module parameters are now defined in
one place at i915_params.c. Plus you can do this to find all module
parameter references:

$ git grep "i915\." -- drivers/gpu/drm/i915

v2:
- move the definitions into a new file
- s/i915_params/i915/
- make i915_try_reset i915.reset, for consistency

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 82c4605..a071748 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -38,120 +38,6 @@
 #include <linux/module.h>
 #include <drm/drm_crtc_helper.h>
 
-static int i915_modeset __read_mostly = -1;
-module_param_named(modeset, i915_modeset, int, 0400);
-MODULE_PARM_DESC(modeset,
-		"Use kernel modesetting [KMS] (0=DRM_I915_KMS from .config, "
-		"1=on, -1=force vga console preference [default])");
-
-int i915_panel_ignore_lid __read_mostly = 1;
-module_param_named(panel_ignore_lid, i915_panel_ignore_lid, int, 0600);
-MODULE_PARM_DESC(panel_ignore_lid,
-		"Override lid status (0=autodetect, 1=autodetect disabled [default], "
-		"-1=force lid closed, -2=force lid open)");
-
-unsigned int i915_powersave __read_mostly = 1;
-module_param_named(powersave, i915_powersave, int, 0600);
-MODULE_PARM_DESC(powersave,
-		"Enable powersavings, fbc, downclocking, etc. (default: true)");
-
-int i915_semaphores __read_mostly = -1;
-module_param_named(semaphores, i915_semaphores, int, 0400);
-MODULE_PARM_DESC(semaphores,
-		"Use semaphores for inter-ring sync (default: -1 (use per-chip defaults))");
-
-int i915_enable_rc6 __read_mostly = -1;
-module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0400);
-MODULE_PARM_DESC(i915_enable_rc6,
-		"Enable power-saving render C-state 6. "
-		"Different stages can be selected via bitmask values "
-		"(0 = disable; 1 = enable rc6; 2 = enable deep rc6; 4 = enable deepest rc6). "
-		"For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. "
-		"default: -1 (use per-chip default)");
-
-int i915_enable_fbc __read_mostly = -1;
-module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
-MODULE_PARM_DESC(i915_enable_fbc,
-		"Enable frame buffer compression for power savings "
-		"(default: -1 (use per-chip default))");
-
-unsigned int i915_lvds_downclock __read_mostly = 0;
-module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
-MODULE_PARM_DESC(lvds_downclock,
-		"Use panel (LVDS/eDP) downclocking for power savings "
-		"(default: false)");
-
-int i915_lvds_channel_mode __read_mostly;
-module_param_named(lvds_channel_mode, i915_lvds_channel_mode, int, 0600);
-MODULE_PARM_DESC(lvds_channel_mode,
-		 "Specify LVDS channel mode "
-		 "(0=probe BIOS [default], 1=single-channel, 2=dual-channel)");
-
-int i915_panel_use_ssc __read_mostly = -1;
-module_param_named(lvds_use_ssc, i915_panel_use_ssc, int, 0600);
-MODULE_PARM_DESC(lvds_use_ssc,
-		"Use Spread Spectrum Clock with panels [LVDS/eDP] "
-		"(default: auto from VBT)");
-
-int i915_vbt_sdvo_panel_type __read_mostly = -1;
-module_param_named(vbt_sdvo_panel_type, i915_vbt_sdvo_panel_type, int, 0600);
-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)");
-
-static bool i915_try_reset __read_mostly = true;
-module_param_named(reset, i915_try_reset, bool, 0600);
-MODULE_PARM_DESC(reset, "Attempt GPU resets (default: true)");
-
-bool i915_enable_hangcheck __read_mostly = true;
-module_param_named(enable_hangcheck, i915_enable_hangcheck, bool, 0644);
-MODULE_PARM_DESC(enable_hangcheck,
-		"Periodically check GPU activity for detecting hangs. "
-		"WARNING: Disabling this can cause system wide hangs. "
-		"(default: true)");
-
-int i915_enable_ppgtt __read_mostly = -1;
-module_param_named(i915_enable_ppgtt, i915_enable_ppgtt, int, 0400);
-MODULE_PARM_DESC(i915_enable_ppgtt,
-		"Override PPGTT usage. "
-		"(-1=auto [default], 0=disabled, 1=aliasing, 2=full)");
-
-int i915_enable_psr __read_mostly = 0;
-module_param_named(enable_psr, i915_enable_psr, int, 0600);
-MODULE_PARM_DESC(enable_psr, "Enable PSR (default: false)");
-
-unsigned int i915_preliminary_hw_support __read_mostly = IS_ENABLED(CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT);
-module_param_named(preliminary_hw_support, i915_preliminary_hw_support, int, 0600);
-MODULE_PARM_DESC(preliminary_hw_support,
-		"Enable preliminary hardware support.");
-
-int i915_disable_power_well __read_mostly = 1;
-module_param_named(disable_power_well, i915_disable_power_well, int, 0600);
-MODULE_PARM_DESC(disable_power_well,
-		 "Disable the power well when possible (default: true)");
-
-int i915_enable_ips __read_mostly = 1;
-module_param_named(enable_ips, i915_enable_ips, int, 0600);
-MODULE_PARM_DESC(enable_ips, "Enable IPS (default: true)");
-
-bool i915_fastboot __read_mostly = 0;
-module_param_named(fastboot, i915_fastboot, bool, 0600);
-MODULE_PARM_DESC(fastboot, "Try to skip unnecessary mode sets at boot time "
-		 "(default: false)");
-
-int i915_enable_pc8 __read_mostly = 1;
-module_param_named(enable_pc8, i915_enable_pc8, int, 0600);
-MODULE_PARM_DESC(enable_pc8, "Enable support for low power package C states (PC8+) (default: true)");
-
-int i915_pc8_timeout __read_mostly = 5000;
-module_param_named(pc8_timeout, i915_pc8_timeout, int, 0600);
-MODULE_PARM_DESC(pc8_timeout, "Number of msecs of idleness required to enter PC8+ (default: 5000)");
-
-bool i915_prefault_disable __read_mostly;
-module_param_named(prefault_disable, i915_prefault_disable, bool, 0600);
-MODULE_PARM_DESC(prefault_disable,
-		"Disable page prefaulting for pread/pwrite/reloc (default:false). For developers only.");
-
 static struct drm_driver driver;
 
 static const struct intel_device_info intel_i830_info = {
@@ -480,12 +366,12 @@
 
 	/* Until we get further testing... */
 	if (IS_GEN8(dev)) {
-		WARN_ON(!i915_preliminary_hw_support);
+		WARN_ON(!i915.preliminary_hw_support);
 		return false;
 	}
 
-	if (i915_semaphores >= 0)
-		return i915_semaphores;
+	if (i915.semaphores >= 0)
+		return i915.semaphores;
 
 #ifdef CONFIG_INTEL_IOMMU
 	/* Enable semaphores on SNB when IO remapping is off */
@@ -750,7 +636,7 @@
 	bool simulated;
 	int ret;
 
-	if (!i915_try_reset)
+	if (!i915.reset)
 		return 0;
 
 	mutex_lock(&dev->struct_mutex);
@@ -818,7 +704,7 @@
 	struct intel_device_info *intel_info =
 		(struct intel_device_info *) ent->driver_data;
 
-	if (IS_PRELIMINARY_HW(intel_info) && !i915_preliminary_hw_support) {
+	if (IS_PRELIMINARY_HW(intel_info) && !i915.preliminary_hw_support) {
 		DRM_INFO("This hardware requires preliminary hardware support.\n"
 			 "See CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT, and/or modparam preliminary_hw_support\n");
 		return -ENODEV;
@@ -1049,14 +935,14 @@
 	 * the default behavior.
 	 */
 #if defined(CONFIG_DRM_I915_KMS)
-	if (i915_modeset != 0)
+	if (i915.modeset != 0)
 		driver.driver_features |= DRIVER_MODESET;
 #endif
-	if (i915_modeset == 1)
+	if (i915.modeset == 1)
 		driver.driver_features |= DRIVER_MODESET;
 
 #ifdef CONFIG_VGA_CONSOLE
-	if (vgacon_text_force() && i915_modeset == -1)
+	if (vgacon_text_force() && i915.modeset == -1)
 		driver.driver_features &= ~DRIVER_MODESET;
 #endif