[igt-dev] [i-g-t 1/4] lib/igt_kms: Fix Bigjoiner checks

[Bhanuprakash Modem <bhanuprakash.modem@intel.com>]

Bigjoiner will come in the picture when the resolution > 5K or
clock > max dot-clock. Add a support to check the selected mode
clock is greater than the max dot-clock.

Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
---
 lib/igt_kms.c | 39 +++++++++++++++++++++++++++++++++++++--
 lib/igt_kms.h |  1 +
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index c12823d318e..3587dc7d7f6 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -5780,6 +5780,36 @@ bool igt_max_bpc_constraint(igt_display_t *display, enum pipe pipe,
 	return false;
 }
 
+/*
+ * igt_get_max_dotclock:
+ * @fd: A drm file descriptor
+ *
+ * Get the Max pixel clock frequency from intel specific debugfs
+ * "i915_frequency_info".
+ *
+ * Returns: Max supported pixel clock frequency.
+ */
+int igt_get_max_dotclock(int fd)
+{
+	char buf[4096];
+	char *s;
+	int max_dotclock = 0;
+
+	if (!is_i915_device(fd))
+		return max_dotclock;
+
+	igt_debugfs_read(fd, "i915_frequency_info", buf);
+	s = strstr(buf, "Max pixel clock frequency:");
+	igt_assert(s);
+	igt_assert_eq(sscanf(s, "Max pixel clock frequency: %d kHz", &max_dotclock), 1);
+
+	/* 100 Mhz to 5 GHz seem like reasonable values to expect */
+	igt_assert_lt(max_dotclock, 5000000);
+	igt_assert_lt(100000, max_dotclock);
+
+	return max_dotclock;
+}
+
 /*
  * igt_check_bigjoiner_support:
  * @display: a pointer to an #igt_display_t structure
@@ -5802,6 +5832,7 @@ bool igt_check_bigjoiner_support(igt_display_t *display)
 		enum pipe idx;
 		drmModeModeInfo *mode;
 	} pipes[IGT_MAX_PIPES];
+	int max_dotclock;
 
 	/* Get total enabled pipes. */
 	for_each_pipe(display, p)
@@ -5825,6 +5856,8 @@ bool igt_check_bigjoiner_support(igt_display_t *display)
 		return true;
 	}
 
+	max_dotclock = igt_get_max_dotclock(display->drm_fd);
+
 	/*
 	 * if mode.hdisplay > 5120, then ignore
 	 *  - if the consecutive pipe is not available
@@ -5836,11 +5869,13 @@ bool igt_check_bigjoiner_support(igt_display_t *display)
 	 *  - current & previous crtcs are consecutive
 	 */
 	for (i = 0; i < pipes_in_use; i++) {
-		if (((pipes[i].mode->hdisplay > MAX_HDISPLAY_PER_PIPE) &&
+		if (((pipes[i].mode->hdisplay > MAX_HDISPLAY_PER_PIPE ||
+		      pipes[i].mode->clock > max_dotclock) &&
 		     ((pipes[i].idx >= (total_pipes - 1)) ||
 		      (!display->pipes[pipes[i].idx + 1].enabled) ||
 		      ((i < (pipes_in_use - 1)) && (abs(pipes[i + 1].idx - pipes[i].idx) <= 1)))) ||
-		    ((i > 0) && (pipes[i - 1].mode->hdisplay > MAX_HDISPLAY_PER_PIPE) &&
+		    ((i > 0) && (pipes[i - 1].mode->hdisplay > MAX_HDISPLAY_PER_PIPE ||
+			         pipes[i - 1].mode->clock > max_dotclock) &&
 		     ((!display->pipes[pipes[i - 1].idx + 1].enabled) ||
 		      (abs(pipes[i].idx - pipes[i - 1].idx) <= 1)))) {
 			igt_debug("Pipe/Output combo is not possible with selected mode(s).\n");
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 2b917925158..20a4ced9ad9 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -990,6 +990,7 @@ void igt_sort_connector_modes(drmModeConnector *connector,
 
 bool igt_max_bpc_constraint(igt_display_t *display, enum pipe pipe,
 		igt_output_t *output, int bpc);
+int igt_get_max_dotclock(int fd);
 bool igt_check_bigjoiner_support(igt_display_t *display);
 bool igt_parse_mode_string(const char *mode_string, drmModeModeInfo *mode);
 bool i915_pipe_output_combo_valid(igt_display_t *display);
-- 
2.40.0