drm/i915: rename preliminary_hw_support to alpha_support

The term "preliminary hardware support" has always caused confusion both
among users and developers. It has always been about preliminary driver
support for new hardware, and not so much about preliminary hardware. Of
course, initially both the software and hardware are in early stages,
but the distinction becomes more clear when the user picks up production
hardware and an older kernel to go with it, with just the early support
we had for the hardware at the time the kernel was released. The user
has to specifically enable the alpha quality *driver* support for the
hardware in that specific kernel version.

Rename preliminary_hw_support to alpha_support to emphasize that the
module parameter, config option, and flag are about software, not about
hardware. Improve the language in help texts and debug logging as well.

This appears to be a good time to do the change, as there are currently
no platforms with preliminary^W alpha support.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477909108-18696-1-git-send-email-jani.nikula@intel.com

drivers/gpu/drm/i915/Kconfig

@@ -36,15 +36,20 @@ config DRM_I915
 
 	  If "M" is selected, the module will be called i915.
 
-config DRM_I915_PRELIMINARY_HW_SUPPORT
-	bool "Enable preliminary support for prerelease Intel hardware by default"
+config DRM_I915_ALPHA_SUPPORT
+	bool "Enable alpha quality support for new Intel hardware by default"
 	depends on DRM_I915
 	default n
 	help
-	  Choose this option if you have prerelease Intel hardware and want the
-	  i915 driver to support it by default.  You can enable such support at
-	  runtime with the module option i915.preliminary_hw_support=1; this
-	  option changes the default for that module option.
+	  Choose this option if you have new Intel hardware and want to enable
+	  the alpha quality i915 driver support for the hardware in this kernel
+	  version. You can also enable the support at runtime using the module
+	  parameter i915.alpha_support=1; this option changes the default for
+	  that module parameter.
+
+	  It is recommended to upgrade to a kernel version with proper support
+	  as soon as it is available. Generally fixes for platforms with alpha
+	  support are not backported to older kernels.
 
 	  If in doubt, say "N".
 

drivers/gpu/drm/i915/i915_drv.h

@@ -655,7 +655,7 @@ struct intel_csr {
 	func(is_skylake); \
 	func(is_broxton); \
 	func(is_kabylake); \
-	func(is_preliminary); \
+	func(is_alpha_support); \
 	/* Keep has_* in alphabetical order */ \
 	func(has_64bit_reloc); \
 	func(has_csr); \
@@ -2473,7 +2473,7 @@ struct drm_i915_cmd_table {
 #define IS_SKL_GT4(dev_priv)	(IS_SKYLAKE(dev_priv) && \
 				 (INTEL_DEVID(dev_priv) & 0x00F0) == 0x0030)
 
-#define IS_PRELIMINARY_HW(intel_info) ((intel_info)->is_preliminary)
+#define IS_ALPHA_SUPPORT(intel_info) ((intel_info)->is_alpha_support)
 
 #define SKL_REVID_A0		0x0
 #define SKL_REVID_B0		0x1

drivers/gpu/drm/i915/i915_params.c

@@ -39,7 +39,7 @@ struct i915_params i915 __read_mostly = {
 	.enable_hangcheck = true,
 	.enable_ppgtt = -1,
 	.enable_psr = -1,
-	.preliminary_hw_support = IS_ENABLED(CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT),
+	.alpha_support = IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT),
 	.disable_power_well = -1,
 	.enable_ips = 1,
 	.fastboot = 0,
@@ -145,9 +145,10 @@ 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_PARM_DESC(preliminary_hw_support,
-	"Enable preliminary hardware support.");
+module_param_named_unsafe(alpha_support, i915.alpha_support, int, 0400);
+MODULE_PARM_DESC(alpha_support,
+	"Enable alpha quality driver support for latest hardware. "
+	"See also CONFIG_DRM_I915_ALPHA_SUPPORT.");
 
 module_param_named_unsafe(disable_power_well, i915.disable_power_well, int, 0400);
 MODULE_PARM_DESC(disable_power_well,

drivers/gpu/drm/i915/i915_params.h

@@ -40,7 +40,7 @@ struct i915_params {
 	int enable_ppgtt;
 	int enable_execlists;
 	int enable_psr;
-	unsigned int preliminary_hw_support;
+	unsigned int alpha_support;
 	int disable_power_well;
 	int enable_ips;
 	int invert_brightness;

drivers/gpu/drm/i915/i915_pci.c

@@ -439,9 +439,10 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct intel_device_info *intel_info =
 		(struct intel_device_info *) ent->driver_data;
 
-	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");
+	if (IS_ALPHA_SUPPORT(intel_info) && !i915.alpha_support) {
+		DRM_INFO("The driver support for your hardware in this kernel version is alpha quality\n"
+			 "See CONFIG_DRM_I915_ALPHA_SUPPORT or i915.alpha_support module parameter\n"
+			 "to enable support in this kernel version, or check for kernel updates.\n");
 		return -ENODEV;
 	}