|
Hello All, Please find a proposed workaround patch for a weathered colours (incorrect assignment to Limited RGB setting) issue. The weathered colour issue is documented at: https://bugs.archlinux.org/task/46472 https://wiki.archlinux.org/index.php/Intel_graphics#Weathered_colors_.28color_range_problem.29 https://losca.blogspot.com.au/2013/11/workaround-for-setting-full-rgb-when.html This patch, which I have shared with Jesse Barnes, provides a kernel command line option "i915.rgb_mode" with two usable options: i915.rgb_mode=1 gives forced Full RGB Mode; i915.rgb_mode=2 gives forced Limited RGB Mode. Any other value passed to i915.rgb_mode will call the default Automatic RGB mode. A limitation of this patch is that the KMS framebuffer needs to be interrupted, such as occurs when xorg-server starts. i.e. if xorg-server were not to be started, the weathered colour issue remains in effect, even with a switch from one tty to another. For reference, the machine that I am testing on is a 4770k (Haswell, Core i7). I am investigating the issue further to improve this workaround so that the change from KMS to xorg-server is not required for the patch to come into effect. I have tested this patch on Debian Testing. -Damien Sticklen |
diff -ruN linux-4.8.1/drivers/gpu/drm/i915/i915_params.c linux-4.8.1-patched/drivers/gpu/drm/i915/i915_params.c
--- linux-4.8.1/drivers/gpu/drm/i915/i915_params.c 2016-10-07 21:03:33.000000000 +0800
+++ linux-4.8.1-patched/drivers/gpu/drm/i915/i915_params.c 2016-10-18 21:36:12.051442687 +0800
@@ -54,6 +54,7 @@
.verbose_state_checks = 1,
.nuclear_pageflip = 0,
.edp_vswing = 0,
+ .rgb_mode = 0,
.enable_guc_loading = 0,
.enable_guc_submission = 0,
.guc_log_level = -1,
@@ -200,6 +201,10 @@
"(0=use value from vbt [default], 1=low power swing(200mV),"
"2=default swing(400mV))");
+/* Override for the RGB Mode Auto detection that was introduced in Linux 3.8. This will provide the user with FULL, and LIMITED on the kernel commandline */
+module_param_named(rgb_mode, i915.rgb_mode, int, 0400);
+MODULE_PARM_DESC(rgb_mode, "Override RGB Mode (1=Full RGB MODE, 2=Limited RGB Mode; Default: 0 (Automatic RGB Mode - Lets the driver select))");
+
module_param_named_unsafe(enable_guc_loading, i915.enable_guc_loading, int, 0400);
MODULE_PARM_DESC(enable_guc_loading,
"Enable GuC firmware loading "
diff -ruN linux-4.8.1/drivers/gpu/drm/i915/i915_params.h linux-4.8.1-patched/drivers/gpu/drm/i915/i915_params.h
--- linux-4.8.1/drivers/gpu/drm/i915/i915_params.h 2016-10-07 21:03:33.000000000 +0800
+++ linux-4.8.1-patched/drivers/gpu/drm/i915/i915_params.h 2016-10-18 21:36:12.059442587 +0800
@@ -51,6 +51,7 @@
int use_mmio_flip;
int mmio_debug;
int edp_vswing;
+ int rgb_mode; /* Do not allow the kernel to select the output color width */
unsigned int inject_load_failure;
/* leave bools at the end to not create holes */
bool enable_hangcheck;
diff -ruN linux-4.8.1/drivers/gpu/drm/i915/intel_hdmi.c linux-4.8.1-patched/drivers/gpu/drm/i915/intel_hdmi.c
--- linux-4.8.1/drivers/gpu/drm/i915/intel_hdmi.c 2016-10-07 21:03:33.000000000 +0800
+++ linux-4.8.1-patched/drivers/gpu/drm/i915/intel_hdmi.c 2016-10-18 21:36:12.059442587 +0800
@@ -1585,7 +1585,22 @@
goto done;
}
+ /* Implement the RGB Override specified on the kernel command line*/
if (property == dev_priv->broadcast_rgb_property) {
+ if (i915.rgb_mode == 1) {
+ intel_hdmi->color_range_auto = false;
+ intel_hdmi->limited_color_range = false;
+
+ goto done;
+ }
+ else if (i915.rgb_mode == 2) {
+ intel_hdmi->color_range_auto = false;
+ intel_hdmi->limited_color_range = true;
+
+ goto done;
+ }
+
+ /* If an override option is not provided in the kernel commandline, let the driver select the mode */
bool old_auto = intel_hdmi->color_range_auto;
bool old_range = intel_hdmi->limited_color_range;
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