DRM: i915: add mode setting support

This commit adds i915 driver support for the DRM mode setting APIs.
Currently, VGA, LVDS, SDVO DVI & VGA, TV and DVO LVDS outputs are
supported.  HDMI, DisplayPort and additional SDVO output support will
follow.

Support for the mode setting code is controlled by the new 'modeset'
module option.  A new config option, CONFIG_DRM_I915_KMS controls the
default behavior, and whether a PCI ID list is built into the module for
use by user level module utilities.

Note that if mode setting is enabled, user level drivers that access
display registers directly or that don't use the kernel graphics memory
manager will likely corrupt kernel graphics memory, disrupt output
configuration (possibly leading to hangs and/or blank displays), and
prevent panic/oops messages from appearing.  So use caution when
enabling this code; be sure your user level code supports the new
interfaces.

A new SysRq key, 'g', provides emergency support for switching back to
the kernel's framebuffer console; which is useful for testing.

Co-authors: Dave Airlie <airlied@linux.ie>, Hong Liu <hong.liu@intel.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e0d996ed9026..cbee41c32417 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -33,11 +33,22 @@
 #include "i915_drv.h"
 
 #include "drm_pciids.h"
+#include <linux/console.h>
+
+unsigned int i915_modeset = -1;
+module_param_named(modeset, i915_modeset, int, 0400);
+
+unsigned int i915_fbpercrtc = 0;
+module_param_named(fbpercrtc, i915_fbpercrtc, int, 0400);
 
 static struct pci_device_id pciidlist[] = {
 	i915_PCI_IDS
 };
 
+#if defined(CONFIG_DRM_I915_KMS)
+MODULE_DEVICE_TABLE(pci, pciidlist);
+#endif
+
 static int i915_suspend(struct drm_device *dev, pm_message_t state)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -148,6 +159,28 @@ static struct drm_driver driver = {
 static int __init i915_init(void)
 {
 	driver.num_ioctls = i915_max_ioctl;
+
+	/*
+	 * If CONFIG_DRM_I915_KMS is set, default to KMS unless
+	 * explicitly disabled with the module pararmeter.
+	 *
+	 * Otherwise, just follow the parameter (defaulting to off).
+	 *
+	 * Allow optional vga_text_mode_force boot option to override
+	 * the default behavior.
+	 */
+#if defined(CONFIG_DRM_I915_KMS)
+	if (i915_modeset != 0)
+		driver.driver_features |= DRIVER_MODESET;
+#endif
+	if (i915_modeset == 1)
+		driver.driver_features |= DRIVER_MODESET;
+
+#ifdef CONFIG_VGA_CONSOLE
+	if (vgacon_text_force() && i915_modeset == -1)
+		driver.driver_features &= ~DRIVER_MODESET;
+#endif
+
 	return drm_init(&driver);
 }