[PATCH xserver] xfree86: Refine drm modes on continuous freq panel

[Aaron Ma]

EDID1.4 replaced GTF Bit with Continuous or Non-Continuous Frequency Display.

Check the "Display Range Limits Descriptor" for GTF support.
If panel doesn't support GTF, then add gtf modes.

Otherwise X will only show the modes in "Detailed Timing Descriptor".

BugLink: https://gitlab.freedesktop.org/drm/intel/issues/313
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 hw/xfree86/ddc/edid.h                         |  6 ++++
 hw/xfree86/ddc/interpret_edid.c               | 32 +++++++++++++++++++
 hw/xfree86/ddc/xf86DDC.h                      |  3 ++
 .../drivers/modesetting/drmmode_display.c     |  2 +-
 4 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/hw/xfree86/ddc/edid.h b/hw/xfree86/ddc/edid.h
index 750e4270b..dffcb3749 100644
--- a/hw/xfree86/ddc/edid.h
+++ b/hw/xfree86/ddc/edid.h
@@ -262,6 +262,10 @@
 #define MAX_H (_MAX_H(c) + _MAX_H_OFFSET(c))
 #define _MAX_CLOCK(x) x[9]
 #define MAX_CLOCK _MAX_CLOCK(c)
+#define _DEFAULT_GTF(x) (x[10] == 0x00)
+#define DEFAULT_GTF _DEFAULT_GTF(c)
+#define _RANGE_LIMITS_ONLY(x) (x[10] == 0x01)
+#define RANGE_LIMITS_ONLY _RANGE_LIMITS_ONLY(c)
 #define _HAVE_2ND_GTF(x) (x[10] == 0x02)
 #define HAVE_2ND_GTF _HAVE_2ND_GTF(c)
 #define _F_2ND_GTF(x) (x[12] * 2)
@@ -490,6 +494,8 @@ struct monitor_ranges {
     int gtf_2nd_j;
     int max_clock_khz;
     int maxwidth;               /* in pixels */
+    BOOL supported_default_gtf;
+    BOOL range_limits_only;
     char supported_aspect;
     char preferred_aspect;
     char supported_blanking;
diff --git a/hw/xfree86/ddc/interpret_edid.c b/hw/xfree86/ddc/interpret_edid.c
index 17a8f81c0..4f3cbc587 100644
--- a/hw/xfree86/ddc/interpret_edid.c
+++ b/hw/xfree86/ddc/interpret_edid.c
@@ -672,7 +672,19 @@ get_monitor_ranges(Uchar * c, struct monitor_ranges *r)
     r->max_clock = 0;
     if (MAX_CLOCK != 0xff)      /* is specified? */
         r->max_clock = MAX_CLOCK * 10 + 5;
+
+    if (DEFAULT_GTF) {
+	r->supported_default_gtf = TRUE;
+    } else
+	r->supported_default_gtf = FALSE;
+
+    if (RANGE_LIMITS_ONLY) {
+	r->range_limits_only = TRUE;
+    } else
+	r->range_limits_only = FALSE;
+
     if (HAVE_2ND_GTF) {
+        r->supported_default_gtf = TRUE;
         r->gtf_2nd_f = F_2ND_GTF;
         r->gtf_2nd_c = C_2ND_GTF;
         r->gtf_2nd_m = M_2ND_GTF;
@@ -751,6 +763,26 @@ validate_version(int scrnIndex, struct edid_version *r)
     return TRUE;
 }
 
+Bool
+gtf_supported(int scrnIndex, xf86MonPtr mon)
+{
+    struct detailed_monitor_section *det_timing_des = mon->det_mon;
+    int i;
+
+    if (mon && (mon->ver.revision < 4)) {
+        if (GTF_SUPPORTED(mon->features.msc))
+	    return TRUE;
+    } else {
+        for (i = 0; i < DET_TIMINGS; det_timing_des = &(mon->det_mon[++i])) {
+	    if ((det_timing_des) && (det_timing_des->type == DS_RANGES))
+	        if (det_timing_des->section.ranges.supported_default_gtf)
+		    return TRUE;
+	}
+    }
+
+    return FALSE;
+}
+
 /*
  * Returns true if HDMI, false if definitely not or unknown.
  */
diff --git a/hw/xfree86/ddc/xf86DDC.h b/hw/xfree86/ddc/xf86DDC.h
index 7d81ab911..2fa4ba55a 100644
--- a/hw/xfree86/ddc/xf86DDC.h
+++ b/hw/xfree86/ddc/xf86DDC.h
@@ -48,6 +48,9 @@ extern _X_EXPORT Bool xf86SetDDCproperties(ScrnInfoPtr pScreen, xf86MonPtr DDC);
 extern _X_EXPORT Bool
  xf86MonitorIsHDMI(xf86MonPtr mon);
 
+extern _X_EXPORT Bool
+gtf_supported(int scrnIndex, xf86MonPtr mon);
+
 extern _X_EXPORT DisplayModePtr
 FindDMTMode(int hsize, int vsize, int refresh, Bool rb);
 
diff --git a/hw/xfree86/drivers/modesetting/drmmode_display.c b/hw/xfree86/drivers/modesetting/drmmode_display.c
index 8e6b697c4..031e5efea 100644
--- a/hw/xfree86/drivers/modesetting/drmmode_display.c
+++ b/hw/xfree86/drivers/modesetting/drmmode_display.c
@@ -2459,7 +2459,7 @@ drmmode_output_add_gtf_modes(xf86OutputPtr output, DisplayModePtr Modes)
     int max_x = 0, max_y = 0;
     float max_vrefresh = 0.0;
 
-    if (mon && GTF_SUPPORTED(mon->features.msc))
+    if (mon && gtf_supported(output->scrn->scrnIndex, mon))
         return Modes;
 
     if (!has_panel_fitter(output))
-- 
2.26.0