[PATCH i-g-t 2/3] lib/igt_kms: Add support to check joiner mode limit

[Jeevan B <jeevan.b@intel.com>]

Added library changes to find the highest non-joiner mode.
This helps to get the mode that does not require a big joiner.

v2: Update commit message, create a new library function
    to get max hdisplay and fix condtion for selecting mode.
v3: Update function name.

Signed-off-by: Jeevan B <jeevan.b@intel.com>
---
 lib/igt_kms.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 3caba7d77..e1a74a3ee 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -6406,6 +6406,51 @@ bool bigjoiner_mode_found(int drm_fd, drmModeConnector *connector,
 	return found;
 }
 
+/**
+ * get_max_hdisplay:
+ * @drm_fd: drm file descriptor
+ *
+ * Returns: The maximum hdisplay supported per pipe.
+ */
+static int get_max_hdisplay(int drm_fd)
+{
+	int dev_id = intel_get_drm_devid(drm_fd);
+
+	return (intel_display_ver(dev_id) >= 30) ? HDISPLAY_6K_PER_PIPE :
+						   HDISPLAY_5K_PER_PIPE;
+}
+
+/**
+ * max_non_joiner_mode_found:
+ * @drm_fd: drm file descriptor
+ * @connector: libdrm connector
+ * @max_dot_clock: max dot clock frequency
+ * @mode: libdrm mode to be filled
+ *
+ * Finds the highest possible display mode that does
+ * not require a big joiner.
+ *
+ * Returns: True if a valid non-joiner mode is found,
+ * false otherwise.
+ */
+bool max_non_joiner_mode_found(int drm_fd, drmModeConnector *connector,
+			   int max_dotclock, drmModeModeInfo *mode)
+{
+	int max_hdisplay = get_max_hdisplay(drm_fd);
+
+	for (int i = 0; i < connector->count_modes; i++) {
+		drmModeModeInfo *current_mode = &connector->modes[i];
+
+		if (current_mode->hdisplay == max_hdisplay &&
+		    current_mode->clock < max_dotclock) {
+			*mode = *current_mode;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /**
  * igt_is_joiner_enabled_for_pipe:
  * @drmfd: A drm file descriptor
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 1cfacf87d..7227f0b0e 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1245,6 +1245,8 @@ int igt_get_max_dotclock(int fd);
 bool igt_bigjoiner_possible(int drm_fd, drmModeModeInfo *mode, int max_dotclock);
 bool bigjoiner_mode_found(int drm_fd, drmModeConnector *connector,
 			  int max_dotclock, drmModeModeInfo *mode);
+bool max_non_joiner_mode_found(int drm_fd, drmModeConnector *connector,
+			       int max_dotclock, drmModeModeInfo *mode);
 bool igt_is_joiner_enabled_for_pipe(int drmfd, enum pipe pipe);
 bool igt_ultrajoiner_possible(drmModeModeInfo *mode, int max_dotclock);
 bool ultrajoiner_mode_found(int drm_fd, drmModeConnector *connector,
-- 
2.25.1