[ 221/221] drm/i915: Treat crtc->mode.clock == 0 as disabled

Greg Kroah-Hartman
2013-01-15T22:36:53Z

From: Chris Wilson <chris@chris-wilson.co.uk>

commit 3490ea5de6ac4af309c3df8a26a5cca61306334c upstream.

Prevent a divide-by-zero by consistently treating an 'active' CRTC
without a mode set as actually disabled.

This looks to have been first introduced with

commit 24929352481f085c5f85d4d4cbc919ddf106d381
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Mon Jul 2 20:28:59 2012 +0200

drm/i915: read out the modeset hw state at load and resume time

but then combined with

commit b0a2658acb5bf9ca86b4aab011b7106de3af0add
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Tue Dec 18 09:37:54 2012 +0100

drm/i915: don't disable disconnected outputs

it finally started oopsing.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/i915/intel_pm.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -44,6 +44,14 @@
* i915.i915_enable_fbc parameter
*/

+static bool intel_crtc_active(struct drm_crtc *crtc)
+{
+ /* Be paranoid as we can arrive here with only partial
+ * state retrieved from the hardware during setup.
+ */
+ return to_intel_crtc(crtc)->active && crtc->fb && crtc->mode.clock;
+}
+
static void i8xx_disable_fbc(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -405,9 +413,8 @@ void intel_update_fbc(struct drm_device
* - going to an unsupported config (interlace, pixel multiply, etc.)
*/
list_for_each_entry(tmp_crtc, &dev->mode_config.crtc_list, head) {
- if (tmp_crtc->enabled &&
- !to_intel_crtc(tmp_crtc)->primary_disabled &&
- tmp_crtc->fb) {
+ if (intel_crtc_active(tmp_crtc) &&
+ !to_intel_crtc(tmp_crtc)->primary_disabled) {
if (crtc) {
DRM_DEBUG_KMS("more than one pipe active, disabling compression\n");
dev_priv->no_fbc_reason = FBC_MULTIPLE_PIPES;
@@ -992,7 +999,7 @@ static struct drm_crtc *single_enabled_c
struct drm_crtc *crtc, *enabled = NULL;

list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
- if (crtc->enabled && crtc->fb) {
+ if (intel_crtc_active(crtc)) {
if (enabled)
return NULL;
enabled = crtc;
@@ -1086,7 +1093,7 @@ static bool g4x_compute_wm0(struct drm_d
int entries, tlb_miss;

crtc = intel_get_crtc_for_plane(dev, plane);
- if (crtc->fb == NULL || !crtc->enabled) {
+ if (!intel_crtc_active(crtc)) {
*cursor_wm = cursor->guard_size;
*plane_wm = display->guard_size;
return false;
@@ -1215,7 +1222,7 @@ static bool vlv_compute_drain_latency(st
int entries;

crtc = intel_get_crtc_for_plane(dev, plane);
- if (crtc->fb == NULL || !crtc->enabled)
+ if (!intel_crtc_active(crtc))
return false;

clock = crtc->mode.clock; /* VESA DOT Clock */
@@ -1478,7 +1485,7 @@ static void i9xx_update_wm(struct drm_de

fifo_size = dev_priv->display.get_fifo_size(dev, 1);
crtc = intel_get_crtc_for_plane(dev, 1);
- if (crtc->enabled && crtc->fb) {
+ if (intel_crtc_active(crtc)) {
planeb_wm = intel_calculate_wm(crtc->mode.clock,
wm_info, fifo_size,
crtc->fb->bits_per_pixel / 8,
@@ -1923,7 +1930,7 @@ sandybridge_compute_sprite_wm(struct drm
int entries, tlb_miss;

crtc = intel_get_crtc_for_plane(dev, plane);
- if (crtc->fb == NULL || !crtc->enabled) {
+ if (!intel_crtc_active(crtc)) {
*sprite_wm = display->guard_size;
return false;
}