drm_hwcomposer: uses edid DTD to get better estimate of dpi
Edid are not the most reliable when it comes to panel size, however it
seems like preferred DTD are slightly more reliable. This change moves
from the drm parse edid display size to the first preferred DTD to try
improve dpi accuracy.
If no preferred DTD is available we still fallback to the display size.
Change-Id: Ibcc95da9f38ba74e9b95b9d68587b38efbed8de2
signed-off-by: Lucas Berthou <berlu@google.com>
diff --git a/hwc2_device/HwcDisplay.cpp b/hwc2_device/HwcDisplay.cpp
index 42ebd63..9db384b 100644
--- a/hwc2_device/HwcDisplay.cpp
+++ b/hwc2_device/HwcDisplay.cpp
@@ -316,6 +316,19 @@
return changed_layers;
}
+auto HwcDisplay::GetDisplayBoundsMm() -> std::pair<int32_t, int32_t> {
+
+ const auto bounds = GetEdid()->GetBoundsMm();
+ if (bounds.first > 0 || bounds.second > 0) {
+ return bounds;
+ }
+
+ ALOGE("Failed to get display bounds for d=%d\n", int(handle_));
+ // mm_width and mm_height are unreliable. so only provide mm_width to avoid
+ // wrong dpi computations or other use of the values.
+ return {configs_.mm_width, -1};
+}
+
auto HwcDisplay::AcceptValidatedComposition() -> void {
for (std::pair<const hwc2_layer_t, HwcLayer> &l : layers_) {
l.second.AcceptTypeChange();
@@ -549,15 +562,25 @@
*value = hwc_config.mode.GetVSyncPeriodNs();
break;
case HWC2::Attribute::DpiY:
- // ideally this should be vdisplay/mm_heigth, however mm_height
- // comes from edid parsing and is highly unreliable. Viewing the
- // rarity of anisotropic displays, falling back to a single value
- // for dpi yield more correct output.
+ *value = GetEdid()->GetDpiY();
+ if (*value < 0) {
+ // default to raw mode DpiX for both x and y when no good value
+ // can be provided from edid.
+ *value = mm_width ? int(hwc_config.mode.GetRawMode().hdisplay *
+ kUmPerInch / mm_width)
+ : -1;
+ }
+ break;
case HWC2::Attribute::DpiX:
// Dots per 1000 inches
- *value = mm_width ? int(hwc_config.mode.GetRawMode().hdisplay *
- kUmPerInch / mm_width)
- : -1;
+ *value = GetEdid()->GetDpiX();
+ if (*value < 0) {
+ // default to raw mode DpiX for both x and y when no good value
+ // can be provided from edid.
+ *value = mm_width ? int(hwc_config.mode.GetRawMode().hdisplay *
+ kUmPerInch / mm_width)
+ : -1;
+ }
break;
#if __ANDROID_API__ > 29
case HWC2::Attribute::ConfigGroup: