[PATCHv4 1/3] drm/i915: Make finding unused crtc as a generic function

Durgadoss R
2016-04-18T12:51:53Z

Looping over the crtc list and finding an unused crtc
has other users like upfront link training. Hence move it to
a common function to re-use the logic.

v4:
* Added ERR_PTR as a return value in kernel Doc comment (Ander)
v3:
* Added kernel Doc and removed an invalid comment (Ander)
* Rebased on top of latest code which includes locking
for state->enable usage.
v2:
* Made this as a separate function instead of having it
inside upfront link train code.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 74 +++++++++++++++++++++---------------
drivers/gpu/drm/i915/intel_drv.h | 2 +
2 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4cca155..a6df48b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10404,6 +10404,43 @@ static int intel_modeset_setup_plane_state(struct drm_atomic_state *state,
return 0;
}

+/**
+ * intel_get_unused_crtc - Find an unused crtc for the given encoder
+ * @encoder: drm_encoder structure
+ * @ctx: ctx pointer to use with locking
+ *
+ * This function tries to find an unused crtc that can drive
+ * the given encoder. Returns NULL or ERR_PTR on failure.
+ */
+struct drm_crtc *intel_get_unused_crtc(struct drm_encoder *encoder,
+ struct drm_modeset_acquire_ctx *ctx)
+{
+ struct drm_crtc *possible_crtc;
+ struct drm_crtc *crtc = NULL;
+ struct drm_device *dev = encoder->dev;
+ int ret, i = -1;
+
+ for_each_crtc(dev, possible_crtc) {
+ i++;
+ if (!(encoder->possible_crtcs & (1 << i)))
+ continue;
+
+ ret = drm_modeset_lock(&possible_crtc->mutex, ctx);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (possible_crtc->state->enable) {
+ drm_modeset_unlock(&possible_crtc->mutex);
+ continue;
+ }
+
+ crtc = possible_crtc;
+ break;
+ }
+
+ return crtc;
+}
+
bool intel_get_load_detect_pipe(struct drm_connector *connector,
struct drm_display_mode *mode,
struct intel_load_detect_pipe *old,
@@ -10412,7 +10449,6 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
struct intel_crtc *intel_crtc;
struct intel_encoder *intel_encoder =
intel_attached_encoder(connector);
- struct drm_crtc *possible_crtc;
struct drm_encoder *encoder = &intel_encoder->base;
struct drm_crtc *crtc = NULL;
struct drm_device *dev = encoder->dev;
@@ -10421,7 +10457,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
struct drm_atomic_state *state = NULL, *restore_state = NULL;
struct drm_connector_state *connector_state;
struct intel_crtc_state *crtc_state;
- int ret, i = -1;
+ int ret;

DRM_DEBUG_KMS("[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
connector->base.id, connector->name,
@@ -10451,39 +10487,15 @@ retry:
ret = drm_modeset_lock(&crtc->mutex, ctx);
if (ret)
goto fail;
-
- /* Make sure the crtc and connector are running */
- goto found;
- }
-
- /* Find an unused one (if possible) */
- for_each_crtc(dev, possible_crtc) {
- i++;
- if (!(encoder->possible_crtcs & (1 << i)))
- continue;
-
- ret = drm_modeset_lock(&possible_crtc->mutex, ctx);
- if (ret)
+ } else {
+ crtc = intel_get_unused_crtc(encoder, ctx);
+ if (IS_ERR_OR_NULL(crtc)) {
+ ret = PTR_ERR_OR_ZERO(crtc);
+ DRM_DEBUG_KMS("no pipe available for load-detect\n");
goto fail;
-
- if (possible_crtc->state->enable) {
- drm_modeset_unlock(&possible_crtc->mutex);
- continue;
}
-
- crtc = possible_crtc;
- break;
- }
-
- /*
- * If we didn't find an unused CRTC, don't use any.
- */
- if (!crtc) {
- DRM_DEBUG_KMS("no pipe available for load-detect\n");
- goto fail;
}

-found:
intel_crtc = to_intel_crtc(crtc);

ret = drm_modeset_lock(&crtc->primary->mutex, ctx);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index e13ce22..27b5dcd 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1159,6 +1159,8 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
void intel_release_load_detect_pipe(struct drm_connector *connector,
struct intel_load_detect_pipe *old,
struct drm_modeset_acquire_ctx *ctx);
+struct drm_crtc *intel_get_unused_crtc(struct drm_encoder *encoder,
+ struct drm_modeset_acquire_ctx *ctx);
int intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
unsigned int rotation);
struct drm_framebuffer *
--
1.9.1