allow to force graphics mode

This patch adds in a system property "debug.drm.mode.force", which works
*similarly* to "debug.drm.mode". XRESxYRES[@REFRESHRATE].

1 files changed, 137 insertions, 20 deletions

diff --git a/gralloc_drm_kms.c b/gralloc_drm_kms.c
index 547b70c..0909361 100644
--- a/gralloc_drm_kms.c
+++ b/gralloc_drm_kms.c
@@ -31,6 +31,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <poll.h>
+#include <math.h>
 #include "gralloc_drm.h"
 #include "gralloc_drm_priv.h"
 #include <hardware_legacy/uevent.h>
@@ -683,12 +684,104 @@ static void drm_kms_init_features(struct gralloc_drm_t *drm)
 	ALOGD("will use %s for fb posting", swap_mode);
 }
 
+#define MARGIN_PERCENT 1.8   /* % of active vertical image*/
+#define CELL_GRAN 8.0   /* assumed character cell granularity*/
+#define MIN_PORCH 1 /* minimum front porch   */
+#define V_SYNC_RQD 3 /* width of vsync in lines   */
+#define H_SYNC_PERCENT 8.0   /* width of hsync as % of total line */
+#define MIN_VSYNC_PLUS_BP 550.0 /* min time of vsync + back porch (microsec) */
+#define M 600.0 /* blanking formula gradient */
+#define C 40.0  /* blanking formula offset   */
+#define K 128.0 /* blanking formula scaling factor   */
+#define J 20.0  /* blanking formula scaling factor   */
+/* C' and M' are part of the Blanking Duty Cycle computation */
+#define C_PRIME   (((C - J) * K / 256.0) + J)
+#define M_PRIME   (K / 256.0 * M)
+
+static drmModeModeInfoPtr generate_mode(int h_pixels, int v_lines, float freq)
+{
+	float h_pixels_rnd;
+	float v_lines_rnd;
+	float v_field_rate_rqd;
+	float top_margin;
+	float bottom_margin;
+	float interlace;
+	float h_period_est;
+	float vsync_plus_bp;
+	float v_back_porch;
+	float total_v_lines;
+	float v_field_rate_est;
+	float h_period;
+	float v_field_rate;
+	float v_frame_rate;
+	float left_margin;
+	float right_margin;
+	float total_active_pixels;
+	float ideal_duty_cycle;
+	float h_blank;
+	float total_pixels;
+	float pixel_freq;
+	float h_freq;
+
+	float h_sync;
+	float h_front_porch;
+	float v_odd_front_porch_lines;
+	int interlaced = 0;
+	int margins = 0;
+
+	drmModeModeInfoPtr m = malloc(sizeof(drmModeModeInfo));
+
+	h_pixels_rnd = rint((float) h_pixels / CELL_GRAN) * CELL_GRAN;
+	v_lines_rnd = interlaced ? rint((float) v_lines) / 2.0 : rint((float) v_lines);
+	v_field_rate_rqd = interlaced ? (freq * 2.0) : (freq);
+	top_margin = margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0);
+	bottom_margin = margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0);
+	interlace = interlaced ? 0.5 : 0.0;
+	h_period_est = (((1.0 / v_field_rate_rqd) - (MIN_VSYNC_PLUS_BP / 1000000.0)) / (v_lines_rnd + (2 * top_margin) + MIN_PORCH + interlace) * 1000000.0);
+	vsync_plus_bp = rint(MIN_VSYNC_PLUS_BP / h_period_est);
+	v_back_porch = vsync_plus_bp - V_SYNC_RQD;
+	total_v_lines = v_lines_rnd + top_margin + bottom_margin + vsync_plus_bp + interlace + MIN_PORCH;
+	v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0;
+	h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est);
+	v_field_rate = 1.0 / h_period / total_v_lines * 1000000.0;
+	v_frame_rate = interlaced ? v_field_rate / 2.0 : v_field_rate;
+	left_margin = margins ? rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : 0.0;
+	right_margin = margins ? rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : 0.0;
+	total_active_pixels = h_pixels_rnd + left_margin + right_margin;
+	ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0);
+	h_blank = rint(total_active_pixels * ideal_duty_cycle / (100.0 - ideal_duty_cycle) / (2.0 * CELL_GRAN)) * (2.0 * CELL_GRAN);
+	total_pixels = total_active_pixels + h_blank;
+	pixel_freq = total_pixels / h_period;
+	h_freq = 1000.0 / h_period;
+	h_sync = rint(H_SYNC_PERCENT / 100.0 * total_pixels / CELL_GRAN) * CELL_GRAN;
+	h_front_porch = (h_blank / 2.0) - h_sync;
+	v_odd_front_porch_lines = MIN_PORCH + interlace;
+
+	m->clock = ceil(pixel_freq) * 1000;
+	m->hdisplay = (int) (h_pixels_rnd);
+	m->hsync_start = (int) (h_pixels_rnd + h_front_porch);
+	m->hsync_end = (int) (h_pixels_rnd + h_front_porch + h_sync);
+	m->htotal = (int) (total_pixels);
+	m->hskew = 0;
+	m->vdisplay = (int) (v_lines_rnd);
+	m->vsync_start = (int) (v_lines_rnd + v_odd_front_porch_lines);
+	m->vsync_end = (int) (int) (v_lines_rnd + v_odd_front_porch_lines + V_SYNC_RQD);
+	m->vtotal = (int) (total_v_lines);
+	m->vscan = 0;
+	m->vrefresh = freq;
+	m->flags = 10;
+	m->type = 64;
+
+	return (m);
+}
+
 static drmModeModeInfoPtr find_mode(drmModeConnectorPtr connector, int *bpp)
 {
 	char value[PROPERTY_VALUE_MAX];
 	drmModeModeInfoPtr mode;
 	int dist, i;
-	int xres = 0, yres = 0;
+	int xres = 0, yres = 0, rate = 0;
+	int forcemode = 0;
 
 	if (property_get("debug.drm.mode", value, NULL)) {
 		char *p = value, *end;
@@ -704,31 +797,50 @@ static drmModeModeInfoPtr find_mode(drmModeConnectorPtr connector, int *bpp)
 			ALOGI("will find the closest match for %dx%d@%d",
 					xres, yres, *bpp);
 		}
-	}
-	else {
+	} else if (property_get("debug.drm.mode.force", value, NULL)) {
+		char *p = value, *end;
+		*bpp = 0;
+
+		/* parse <xres>x<yres>[@<refreshrate>] */
+		if (sscanf(value, "%dx%d@%d", &xres, &yres, &rate) != 3) {
+			rate = 60;
+			if (sscanf(value, "%dx%d", &xres, &yres) != 2)
+				xres = yres = 0;
+		}
+
+		if (xres && yres && rate) {
+			ALOGI("will use %dx%d@%dHz", xres, yres, rate);
+			forcemode = 1;
+		}
+	} else {
 		*bpp = 0;
 	}
 
-	mode = NULL;
 	dist = INT_MAX;
-	for (i = 0; i < connector->count_modes; i++) {
-		drmModeModeInfoPtr m = &connector->modes[i];
-		int tmp;
 
-		if (xres && yres) {
-			tmp = (m->hdisplay - xres) * (m->hdisplay - xres) +
-				(m->vdisplay - yres) * (m->vdisplay - yres);
-		}
-		else {
-			/* use the first preferred mode */
-			tmp = (m->type & DRM_MODE_TYPE_PREFERRED) ? 0 : dist;
-		}
+	if (forcemode)
+		mode = generate_mode(xres, yres, rate);
+	else {
+		mode = NULL;
+		for (i = 0; i < connector->count_modes; i++) {
+			drmModeModeInfoPtr m = &connector->modes[i];
+			int tmp;
+
+			if (xres && yres) {
+				tmp = (m->hdisplay - xres) * (m->hdisplay - xres) +
+					(m->vdisplay - yres) * (m->vdisplay - yres);
+			}
+			else {
+				/* use the first preferred mode */
+				tmp = (m->type & DRM_MODE_TYPE_PREFERRED) ? 0 : dist;
+			}
 
-		if (tmp < dist) {
-			mode = m;
-			dist = tmp;
-			if (!dist)
-				break;
+			if (tmp < dist) {
+				mode = m;
+				dist = tmp;
+				if (!dist)
+					break;
+			}
 		}
 	}
 
@@ -736,6 +848,11 @@ static drmModeModeInfoPtr find_mode(drmModeConnectorPtr connector, int *bpp)
 	if (!mode)
 		mode = &connector->modes[0];
 
+	ALOGI("Established mode:");
+	ALOGI("clock: %d, hdisplay: %d, hsync_start: %d, hsync_end: %d, htotal: %d, hskew: %d", mode->clock, mode->hdisplay, mode->hsync_start, mode->hsync_end, mode->htotal, mode->hskew);
+	ALOGI("vdisplay: %d, vsync_start: %d, vsync_end: %d, vtotal: %d, vscan: %d, vrefresh: %d", mode->vdisplay, mode->vsync_start, mode->vsync_end, mode->vtotal, mode->vscan, mode->vrefresh);
+	ALOGI("flags: %d, type: %d, name %s", mode->flags, mode->type, mode->name);
+
 	*bpp /= 8;
 
 	return mode;