[igt-dev] [PATCH] [i-g-t] tests/amdgpu/amd_link_settings: use mode 640x480 for link configuration test

[Hersen Wu <hersenxs.wu@amd.com>]

with 4k dp connected, amdgpu kernel warning message dp_blank timeout
happens intermittently. link configuration <1, 1.62> could not support
4k mode. dp safe mode 640x480@60hz could be used for all link
configuration test.

video timing bw in bits: pixel_clock x bits_per_color x 3
dp lane bw in bits: link_rate x lane_count x 8 / 10

Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
---
 tests/amdgpu/amd_link_settings.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/tests/amdgpu/amd_link_settings.c b/tests/amdgpu/amd_link_settings.c
index 14c8c4d7..28aa5da5 100644
--- a/tests/amdgpu/amd_link_settings.c
+++ b/tests/amdgpu/amd_link_settings.c
@@ -159,6 +159,21 @@ static void run_link_training_config(data_t *data, igt_output_t *output)
 	}
 }
 
+static const drmModeModeInfo dp_safe_mode_640_480 = {
+	.name		= "640x480",
+	.vrefresh	= 60,
+	.clock		= 25200,
+	.hdisplay	= 640,
+	.hsync_start	= 656,
+	.hsync_end	= 752,
+	.htotal		= 800,
+	.vdisplay	= 480,
+	.vsync_start	= 490,
+	.vsync_end	= 492,
+	.vtotal		= 525,
+	.flags		= DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+};
+
 static void test_link_training_configs(data_t *data)
 {
 	const drmModeModeInfo *orig_mode;
@@ -177,7 +192,12 @@ static void test_link_training_configs(data_t *data)
 		/* Init only if display supports link_settings */
 		test_init(data, output);
 
-		orig_mode = igt_output_get_mode(output);
+		/* run_link_training_config run test from <1, 1.62>
+		 * to highest link configuration. to make sure mode timing
+		 * be fitted into <1, 1.62> and higher configuration, use
+		 * dp safe mode 640x480@60hz
+		 */
+		orig_mode = &dp_safe_mode_640_480;
 		igt_assert(orig_mode);
 		igt_output_override_mode(output, orig_mode);
 
-- 
2.25.1