kernel-ark/drivers/gpu/drm/i915/intel_panel.c
Indan Zupancic 951f3512db drm/i915: Do not handle backlight combination mode specially
The current code does not follow Intel documentation: It misses some things
and does other, undocumented things. This causes wrong backlight values in
certain conditions. Instead of adding tricky code handling badly documented
and rare corner cases, don't handle combination mode specially at all. This
way PCI_LBPC is never touched and weird things shouldn't happen.

If combination mode is enabled, then the only downside is that changing the
brightness has a greater granularity (the LBPC value), but LBPC is at most
254 and the maximum is in the thousands, so this is no real functional loss.

A potential problem with not handling combined mode is that a brightness of
max * PCI_LBPC is not bright enough. However, this is very unlikely because
from the documentation LBPC seems to act as a scaling factor and doesn't look
like it's supposed to be changed after boot. The value at boot should always
result in a bright enough screen.

IMPORTANT: However, although usually the above is true, it may not be when
people ran an older (2.6.37) kernel which messed up the LBPC register, and
they are unlucky enough to have a BIOS that saves and restores the LBPC value.
Then a good kernel may seem to not work: Max brightness isn't bright enough.
If this happens people should boot back into the old kernel, set brightness
to the maximum, and then reboot. After that everything should be fine.

For more information see the below links. This fixes bugs:

  http://bugzilla.kernel.org/show_bug.cgi?id=23472
  http://bugzilla.kernel.org/show_bug.cgi?id=25072

Signed-off-by: Indan Zupancic <indan@nul.nu>
Tested-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-21 15:25:43 -08:00

247 lines
6.9 KiB
C

/*
* Copyright © 2006-2010 Intel Corporation
* Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Dave Airlie <airlied@linux.ie>
* Jesse Barnes <jesse.barnes@intel.com>
* Chris Wilson <chris@chris-wilson.co.uk>
*/
#include "intel_drv.h"
void
intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
struct drm_display_mode *adjusted_mode)
{
adjusted_mode->hdisplay = fixed_mode->hdisplay;
adjusted_mode->hsync_start = fixed_mode->hsync_start;
adjusted_mode->hsync_end = fixed_mode->hsync_end;
adjusted_mode->htotal = fixed_mode->htotal;
adjusted_mode->vdisplay = fixed_mode->vdisplay;
adjusted_mode->vsync_start = fixed_mode->vsync_start;
adjusted_mode->vsync_end = fixed_mode->vsync_end;
adjusted_mode->vtotal = fixed_mode->vtotal;
adjusted_mode->clock = fixed_mode->clock;
drm_mode_set_crtcinfo(adjusted_mode, CRTC_INTERLACE_HALVE_V);
}
/* adjusted_mode has been preset to be the panel's fixed mode */
void
intel_pch_panel_fitting(struct drm_device *dev,
int fitting_mode,
struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int x, y, width, height;
x = y = width = height = 0;
/* Native modes don't need fitting */
if (adjusted_mode->hdisplay == mode->hdisplay &&
adjusted_mode->vdisplay == mode->vdisplay)
goto done;
switch (fitting_mode) {
case DRM_MODE_SCALE_CENTER:
width = mode->hdisplay;
height = mode->vdisplay;
x = (adjusted_mode->hdisplay - width + 1)/2;
y = (adjusted_mode->vdisplay - height + 1)/2;
break;
case DRM_MODE_SCALE_ASPECT:
/* Scale but preserve the aspect ratio */
{
u32 scaled_width = adjusted_mode->hdisplay * mode->vdisplay;
u32 scaled_height = mode->hdisplay * adjusted_mode->vdisplay;
if (scaled_width > scaled_height) { /* pillar */
width = scaled_height / mode->vdisplay;
x = (adjusted_mode->hdisplay - width + 1) / 2;
y = 0;
height = adjusted_mode->vdisplay;
} else if (scaled_width < scaled_height) { /* letter */
height = scaled_width / mode->hdisplay;
y = (adjusted_mode->vdisplay - height + 1) / 2;
x = 0;
width = adjusted_mode->hdisplay;
} else {
x = y = 0;
width = adjusted_mode->hdisplay;
height = adjusted_mode->vdisplay;
}
}
break;
default:
case DRM_MODE_SCALE_FULLSCREEN:
x = y = 0;
width = adjusted_mode->hdisplay;
height = adjusted_mode->vdisplay;
break;
}
done:
dev_priv->pch_pf_pos = (x << 16) | y;
dev_priv->pch_pf_size = (width << 16) | height;
}
static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)
{
u32 val;
/* Restore the CTL value if it lost, e.g. GPU reset */
if (HAS_PCH_SPLIT(dev_priv->dev)) {
val = I915_READ(BLC_PWM_PCH_CTL2);
if (dev_priv->saveBLC_PWM_CTL2 == 0) {
dev_priv->saveBLC_PWM_CTL2 = val;
} else if (val == 0) {
I915_WRITE(BLC_PWM_PCH_CTL2,
dev_priv->saveBLC_PWM_CTL);
val = dev_priv->saveBLC_PWM_CTL;
}
} else {
val = I915_READ(BLC_PWM_CTL);
if (dev_priv->saveBLC_PWM_CTL == 0) {
dev_priv->saveBLC_PWM_CTL = val;
dev_priv->saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_CTL2);
} else if (val == 0) {
I915_WRITE(BLC_PWM_CTL,
dev_priv->saveBLC_PWM_CTL);
I915_WRITE(BLC_PWM_CTL2,
dev_priv->saveBLC_PWM_CTL2);
val = dev_priv->saveBLC_PWM_CTL;
}
}
return val;
}
u32 intel_panel_get_max_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 max;
max = i915_read_blc_pwm_ctl(dev_priv);
if (max == 0) {
/* XXX add code here to query mode clock or hardware clock
* and program max PWM appropriately.
*/
printk_once(KERN_WARNING "fixme: max PWM is zero.\n");
return 1;
}
if (HAS_PCH_SPLIT(dev)) {
max >>= 16;
} else {
if (IS_PINEVIEW(dev)) {
max >>= 17;
} else {
max >>= 16;
if (INTEL_INFO(dev)->gen < 4)
max &= ~1;
}
}
DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);
return max;
}
u32 intel_panel_get_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 val;
if (HAS_PCH_SPLIT(dev)) {
val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
} else {
val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
if (IS_PINEVIEW(dev))
val >>= 1;
}
DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
return val;
}
static void intel_pch_panel_set_backlight(struct drm_device *dev, u32 level)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 val = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
I915_WRITE(BLC_PWM_CPU_CTL, val | level);
}
void intel_panel_set_backlight(struct drm_device *dev, u32 level)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 tmp;
DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
if (HAS_PCH_SPLIT(dev))
return intel_pch_panel_set_backlight(dev, level);
tmp = I915_READ(BLC_PWM_CTL);
if (IS_PINEVIEW(dev)) {
tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);
level <<= 1;
} else
tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
I915_WRITE(BLC_PWM_CTL, tmp | level);
}
void intel_panel_disable_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
if (dev_priv->backlight_enabled) {
dev_priv->backlight_level = intel_panel_get_backlight(dev);
dev_priv->backlight_enabled = false;
}
intel_panel_set_backlight(dev, 0);
}
void intel_panel_enable_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
if (dev_priv->backlight_level == 0)
dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
intel_panel_set_backlight(dev, dev_priv->backlight_level);
dev_priv->backlight_enabled = true;
}
void intel_panel_setup_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
dev_priv->backlight_level = intel_panel_get_backlight(dev);
dev_priv->backlight_enabled = dev_priv->backlight_level != 0;
}