From: Nautiyal, Ankit K <redacted>
Sent: Wednesday, July 28, 2021 5:01 PM
To: Modem, Bhanuprakash <redacted>; igt-
dev@lists.freedesktop.org; Deak, Imre [off-list ref]
Subject: Re: [PATCH i-g-t] tests/kms_setmode: Fix mode selection for Nx tests

Hi Bhanu,

Overall the change looks good to me.

Only one thing that we might want to change is:

We are currently, trying all modes of Display 2 with first mode of
Display 1.

If we exhaust all the modes of Display2, we should go with the 2nd mode
of Display1 and try again.

Instead we just return from that point.

Consider a hypothetical case: Say we have DP and eDP combination mapped
to pipe A and pipe B.

In that case, first we will try first for DP (pipe A) and then try all
modes of eDP.

In case of eDP is having fixed mode, we get out of recursion after
trying the one fixed mode of Display2 and just fail the test, instead of
trying with lower modes of DP.

Please find inline suggestion to fix this:


On 5/26/2021 1:35 AM, Bhanuprakash Modem wrote:

quoted

This patch will find the connector/mode combination that fits
into the bandwidth when more than one monitor is connected.

Example:
   When two monitors connected through MST, the second monitor
   also tries to use the same mode. So two such modes may not
   fit into the link bandwidth. So, iterate through connected
   outputs & modes and find a combination of modes those fit
   into the link BW.

Cc: Imre Deak <redacted>
Cc: Ankit Nautiyal <redacted>
Signed-off-by: Bhanuprakash Modem <redacted>
---
  tests/kms_setmode.c | 95 ++++++++++++++++++++++++++++++++-------------
  1 file changed, 68 insertions(+), 27 deletions(-)

diff --git a/tests/kms_setmode.c b/tests/kms_setmode.c
index eb9ac18964..93ccb829e3 100644
--- a/tests/kms_setmode.c
+++ b/tests/kms_setmode.c

@@ -46,6 +46,9 @@ static int filter_test_id;
  static bool dry_run;
  static bool all_pipes = false;

+static char str_buf[MAX_CRTCS][1024];
+static const char *crtc_strs[MAX_CRTCS];
+
  const drmModeModeInfo mode_640_480 = {
  	.name		= "640x480",
  	.vrefresh	= 60,

@@ -540,44 +543,46 @@ static void check_timings(int crtc_idx, const

drmModeModeInfo *kmode)

quoted

  		     fabs(mean - expected) / line_time(kmode));
  }

-static void test_crtc_config(const struct test_config *tconf,
-			     struct crtc_config *crtcs, int crtc_count)
+static int sort_drm_modes(const void *a, const void *b)
  {
-	char str_buf[MAX_CRTCS][1024];
-	const char *crtc_strs[MAX_CRTCS];
-	struct crtc_config *crtc;
-	static int test_id;
-	bool config_failed = false;
-	int ret = 0;
-	int i;
+	const drmModeModeInfo *mode1 = a, *mode2 = b;

-	test_id++;
+	return (mode1->clock < mode2->clock) - (mode2->clock < mode1->clock);
+}

-	if (filter_test_id && filter_test_id != test_id)
-		return;
+static
+int __test_crtc_config(struct crtc_config *crtcs, int crtc_count,
+		       const struct test_config *tconf, bool *config_failed,
+		       int base)
+{
+	struct crtc_config *crtc = NULL;
+	int ret = 0;

-	igt_info("  Test id#%d CRTC count %d\n", test_id, crtc_count);
+	if (base >= crtc_count)
+		return ret;

-	for (i = 0; i < crtc_count; i++) {
-		get_crtc_config_str(&crtcs[i], str_buf[i], sizeof(str_buf[i]));
-		crtc_strs[i] = &str_buf[i][0];
-	}
+	crtc = &crtcs[base];

-	if (dry_run) {
-		for (i = 0; i < crtc_count; i++)
-			igt_info("    %s\n", crtc_strs[i]);
-		return;
-	}
+	/* Sort the modes in descending order by clock freq. */
+	qsort(crtc->cconfs->connector->modes,
+		crtc->cconfs->connector->count_modes,
+		sizeof(drmModeModeInfo),
+		sort_drm_modes);

-	for (i = 0; i < crtc_count; i++) {
+	for (int i = 0; i < crtc->cconfs->connector->count_modes; i++) {
  		uint32_t *ids;

-		crtc = &crtcs[i];
+		if (!crtc_supports_mode(crtc, &crtc->cconfs->connector->modes[i]))
+			continue;
+
+		crtc->mode = crtc->cconfs->connector->modes[i];

-		igt_info("    %s\n", crtc_strs[i]);
+		get_crtc_config_str(crtc, str_buf[base], sizeof(str_buf[base]));
+		crtc_strs[base] = &str_buf[base][0];
+		igt_info("    %s\n", crtc_strs[base]);

  		create_fb_for_crtc(crtc, &crtc->fb_info);
-		paint_fb(&crtc->fb_info, tconf->name, crtc_strs, crtc_count, i);
+		paint_fb(&crtc->fb_info, tconf->name, crtc_strs, crtc_count, base);

  		ids = get_connector_ids(crtc);
  		if (tconf->flags & TEST_STEALING)

@@ -589,12 +594,48 @@ static void test_crtc_config(const struct test_config

*tconf,

quoted

  		free(ids);

+		if (ret < 0 && errno == ENOSPC)
+			continue;
+
  		if (ret < 0) {
  			igt_assert_eq(errno, EINVAL);
-			config_failed = true;
+			*config_failed = true;
  		}
+
+		return __test_crtc_config(crtcs, crtc_count, tconf, config_failed,

base + 1);

IMHO this should be:

ret = __test_crtc_config(crtcs, crtc_count, tconf, config_failed, base + 1);

Thanks for the review Ankit, I have gone through the logic again.

As recursion calling is inside the loop (list of display modes), It can iterate
over the all modes on each connected display.

And yes, there is a problem with this logic. Even though we find the valid
connector & mode combination, recursion will continue & endup with the minimum
modes. I am trying to find a way to break the recursion when we find the valid
combination. If possible, can you please suggest any solution?

- Bhanu

if (ret < 0 && errno == ENOSPC)

       continue; //continue with next mode of current CRTC

else

       return ret;


Regards,

Ankit

quoted

+	}
+
+	return ret;
+}
+
+static void test_crtc_config(const struct test_config *tconf,
+			     struct crtc_config *crtcs, int crtc_count)
+{
+	static int test_id;
+	bool config_failed = false;
+	int ret = 0;
+	int i;
+
+	test_id++;
+
+	if (filter_test_id && filter_test_id != test_id)
+		return;
+
+	igt_info("  Test id#%d CRTC count %d\n", test_id, crtc_count);
+
+	for (i = 0; i < crtc_count; i++) {
+		get_crtc_config_str(&crtcs[i], str_buf[i], sizeof(str_buf[i]));
+		crtc_strs[i] = &str_buf[i][0];
  	}

+	if (dry_run) {
+		for (i = 0; i < crtc_count; i++)
+			igt_info("    %s\n", crtc_strs[i]);
+		return;
+	}
+
+	ret = __test_crtc_config(crtcs, crtc_count, tconf, &config_failed, 0);
+
  	igt_assert(config_failed == !!(tconf->flags & TEST_INVALID));

  	if (ret == 0 && tconf->flags & TEST_TIMINGS)