From 457d52863d4dfb9d68091fca5716560dd4eb4441 Mon Sep 17 00:00:00 2001
From: Thomas Richter <thor@math.tu-berlin.de>
Date: Sat, 30 May 2015 20:25:53 +0200
Subject: [PATCH 1/1] Fix resume from suspend on IBM X30
This patch fixes the resume from suspend-to-ram on the IBM X30
laptop. The problem is caused by the Bios missing to re-initialize
the iVCH registers, especially the PLL registers.
This patch records the iVCH registers during initialization, and
re-installs this register set when resuming.
Signed-off-by: Thomas Richter <thor@math.tu-berlin.de>
---
drivers/gpu/drm/i915/dvo_ivch.c | 63 +++++++++++++++++++++++++++++++++++----
1 file changed, 57 insertions(+), 6 deletions(-)
@@ -22,6 +22,7 @@
*
* Authors:
* Eric Anholt <eric@anholt.net>
+ * Thomas Richter <thor@math.tu-berlin.de>
*
* Minor modifications (Dithering enable):
* Thomas Richter <thor@math.tu-berlin.de>
@@ -90,7 +91,7 @@
/*
* LCD Vertical Display Size
*/
-#define VR21 0x20
+#define VR21 0x21
/*
* Panel power down status
@@ -155,16 +156,33 @@
# define VR8F_POWER_MASK (0x3c)
# define VR8F_POWER_POS (2)
+/* Some Bios implementations do not restore the DVO state upon
+ * resume from standby. Thus, this driver has to handle it
+ * instead. The following list contains all registers that
+ * require saving.
+ */
+static const uint16_t backup_addresses[] = {
+ 0x11, 0x12,
+ 0x18, 0x19, 0x1a, 0x1f,
+ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+ 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+ 0x8e, 0x8f,
+ 0x10 /* this must come last */
+};
+
struct ivch_priv {
bool quiet;
uint16_t width, height;
+
+ /* Register backup */
+
+ uint16_t reg_backup[ARRAY_SIZE(backup_addresses)];
};
static void ivch_dump_regs(struct intel_dvo_device *dvo);
-
/**
* Reads a register on the ivch.
*
@@ -246,6 +264,7 @@ static bool ivch_init(struct intel_dvo_device *dvo,
{
struct ivch_priv *priv;
uint16_t temp;
+ int i;
priv = kzalloc(sizeof(struct ivch_priv), GFP_KERNEL);
if (priv == NULL)
@@ -273,6 +292,14 @@ static bool ivch_init(struct intel_dvo_device *dvo,
ivch_read(dvo, VR20, &priv->width);
ivch_read(dvo, VR21, &priv->height);
+ /* Make a backup of the registers to be able to restore them
+ * upon suspend.
+ */
+ for (i = 0; i < ARRAY_SIZE(backup_addresses); i++)
+ ivch_read(dvo, backup_addresses[i], priv->reg_backup + i);
+
+ ivch_dump_regs(dvo);
+
return true;
out:
@@ -294,12 +321,31 @@ static enum drm_mode_status ivch_mode_valid(struct intel_dvo_device *dvo,
return MODE_OK;
}
+/* Restore the DVO registers after a resume
+ * from RAM. Registers have been saved during
+ * the initialization.
+ */
+static void ivch_reset(struct intel_dvo_device *dvo)
+{
+ struct ivch_priv *priv = dvo->dev_priv;
+ int i;
+
+ DRM_DEBUG_KMS("Resetting the IVCH registers\n");
+
+ ivch_write(dvo, VR10, 0x0000);
+
+ for (i = 0; i < ARRAY_SIZE(backup_addresses); i++)
+ ivch_write(dvo, backup_addresses[i], priv->reg_backup[i]);
+}
+
/** Sets the power state of the panel connected to the ivch */
static void ivch_dpms(struct intel_dvo_device *dvo, bool enable)
{
int i;
uint16_t vr01, vr30, backlight;
+ ivch_reset(dvo);
+
/* Set the new power state of the panel. */
if (!ivch_read(dvo, VR01, &vr01))
return;
@@ -308,6 +354,7 @@ static void ivch_dpms(struct intel_dvo_device *dvo, bool enable)
backlight = 1;
else
backlight = 0;
+
ivch_write(dvo, VR80, backlight);
if (enable)
@@ -334,6 +381,8 @@ static bool ivch_get_hw_state(struct intel_dvo_device *dvo)
{
uint16_t vr01;
+ ivch_reset(dvo);
+
/* Set the new power state of the panel. */
if (!ivch_read(dvo, VR01, &vr01))
return false;
@@ -348,11 +397,15 @@ static void ivch_mode_set(struct intel_dvo_device *dvo,
struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
{
+ struct ivch_priv *priv = dvo->dev_priv;
uint16_t vr40 = 0;
uint16_t vr01 = 0;
uint16_t vr10;
- ivch_read(dvo, VR10, &vr10);
+ ivch_reset(dvo);
+
+ vr10 = priv->reg_backup[ARRAY_SIZE(backup_addresses) - 1];
+
/* Enable dithering for 18 bpp pipelines */
vr10 &= VR10_INTERFACE_DEPTH_MASK;
if (vr10 == VR10_INTERFACE_2X18 || vr10 == VR10_INTERFACE_1X18)
@@ -366,7 +419,7 @@ static void ivch_mode_set(struct intel_dvo_device *dvo,
uint16_t x_ratio, y_ratio;
vr01 |= VR01_PANEL_FIT_ENABLE;
- vr40 |= VR40_CLOCK_GATING_ENABLE | VR40_ENHANCED_PANEL_FITTING;
+ vr40 |= VR40_CLOCK_GATING_ENABLE;
x_ratio = (((mode->hdisplay - 1) << 16) /
(adjusted_mode->hdisplay - 1)) >> 2;
y_ratio = (((mode->vdisplay - 1) << 16) /
@@ -381,8 +434,6 @@ static void ivch_mode_set(struct intel_dvo_device *dvo,
ivch_write(dvo, VR01, vr01);
ivch_write(dvo, VR40, vr40);
-
- ivch_dump_regs(dvo);
}
static void ivch_dump_regs(struct intel_dvo_device *dvo)
--
1.7.10.4