[idd] config: support fractional refresh rates

Store refresh rates in millihertz and preserve three decimal places.

Advertise exact rational rates while accepting legacy integer values.

Accept rates from 23.900 through 1000.000 Hz.

idd/LGIdd/CSettings.cpp

@@ -21,6 +21,7 @@
 #include "CSettings.h"
 #include "CDebug.h"
 #include "DefaultDisplayModes.h"
+#include "RefreshRate.h"
 
 #include <wdf.h>
 
@@ -34,14 +35,16 @@ CSettings::CSettings()
 
 CSettings::DisplayModes CSettings::LoadModes()
 {
-  const unsigned defaultRefresh = GetDefaultRefresh();
+  const unsigned defaultRefreshMilliHz = GetDefaultRefreshMilliHz();
   DisplayModes displayModes;
 
   bool hasPreferred = false;
   DisplayMode m;
   if (GetExtraMode(m))
   {
-    DEBUG_INFO("ExtraMode: %ux%u@%u%s", m.width, m.height, m.refresh, m.preferred ? "*" : "");
+    const std::wstring refresh = LGFormatRefreshRate(m.refreshMilliHz);
+    DEBUG_INFO("ExtraMode: %ux%u@%ls%s", m.width, m.height,
+      refresh.c_str(), m.preferred ? "*" : "");
     displayModes.push_back(m);
     hasPreferred = m.preferred;
   }
@@ -54,11 +57,12 @@ CSettings::DisplayModes CSettings::LoadModes()
 
     for (int i = 0; i < ARRAYSIZE(DefaultDisplayModes); ++i)
     {
-      m.width     = DefaultDisplayModes[i][0];
-      m.height    = DefaultDisplayModes[i][1];
-      m.refresh   = defaultRefresh;
-      m.preferred = !hasPreferred && (i == DefaultPreferredDisplayMode);
-      m.extraMode = false;
+      m.width          = DefaultDisplayModes[i][0];
+      m.height         = DefaultDisplayModes[i][1];
+      m.refreshMilliHz = defaultRefreshMilliHz;
+      m.preferred      = !hasPreferred &&
+        (i == DefaultPreferredDisplayMode);
+      m.extraMode      = false;
       displayModes.push_back(m);
     }
     return displayModes;
@@ -79,8 +83,9 @@ CSettings::DisplayModes CSettings::LoadModes()
 bool CSettings::SetExtraMode(const DisplayMode& mode)
 {
   WCHAR buf[64];
-  _snwprintf_s(buf, _countof(buf), _TRUNCATE, L"%ux%u@%u%s",
-    mode.width, mode.height, mode.refresh,
+  const std::wstring refresh = LGFormatRefreshRate(mode.refreshMilliHz);
+  _snwprintf_s(buf, _countof(buf), _TRUNCATE, L"%ux%u@%ls%s",
+    mode.width, mode.height, refresh.c_str(),
     mode.preferred ? L"*" : L"");
 
   HKEY  hKey = NULL;
@@ -226,24 +231,45 @@ bool CSettings::GetExtraMode(DisplayMode& mode)
   return true;
 }
 
-unsigned CSettings::GetDefaultRefresh() const
+unsigned CSettings::GetDefaultRefreshMilliHz() const
 {
-  DWORD refresh = 60;
-  DWORD cb      = sizeof(refresh);
-  HKEY  hKey    = nullptr;
+  HKEY hKey = nullptr;
+  LONG status = RegOpenKeyExW(
+    HKEY_LOCAL_MACHINE, LGIDD_REGKEY, 0, KEY_QUERY_VALUE, &hKey);
+  if (status != ERROR_SUCCESS)
+    return 60000;
 
-  LONG st = RegOpenKeyExW(HKEY_LOCAL_MACHINE, LGIDD_REGKEY, 0, KEY_QUERY_VALUE, &hKey);
-  if (st == ERROR_SUCCESS)
+  DWORD type = 0;
+  DWORD size = 0;
+  status = RegQueryValueExW(
+    hKey, L"DefaultRefresh", nullptr, &type, nullptr, &size);
+  if (status != ERROR_SUCCESS)
   {
-    DWORD type = 0;
-    st = RegGetValueW(hKey, nullptr, L"DefaultRefresh", RRF_RT_REG_DWORD, &type, &refresh, &cb);
     RegCloseKey(hKey);
+    return 60000;
   }
 
-  if (st != ERROR_SUCCESS || refresh < 30 || refresh > 1000)
-    return 60;
+  unsigned refreshMilliHz = 0;
+  if (type == REG_DWORD && size == sizeof(DWORD))
+  {
+    DWORD refresh = 0;
+    status = RegQueryValueExW(hKey, L"DefaultRefresh", nullptr, &type,
+      (LPBYTE)&refresh, &size);
+    if (status == ERROR_SUCCESS && refresh >= 24 && refresh <= 1000)
+      refreshMilliHz = refresh * 1000;
+  }
+  else if ((type == REG_SZ || type == REG_EXPAND_SZ) && size &&
+      size % sizeof(wchar_t) == 0)
+  {
+    std::vector<wchar_t> value(size / sizeof(wchar_t) + 1, L'\0');
+    status = RegQueryValueExW(hKey, L"DefaultRefresh", nullptr, &type,
+      (LPBYTE)value.data(), &size);
+    if (status == ERROR_SUCCESS)
+      LGParseRefreshRate(value.data(), refreshMilliHz);
+  }
 
-  return refresh;
+  RegCloseKey(hKey);
+  return refreshMilliHz ? refreshMilliHz : 60000;
 }
 
 bool CSettings::ReadModesValue(std::vector<std::wstring> &out) const
@@ -320,16 +346,14 @@ bool CSettings::ParseModeString(const std::wstring& in, DisplayMode& out)
 
   if (!toUnsigned(s.substr(0, xPos), out.width) ||
       !toUnsigned(s.substr(xPos + 1, atPos - (xPos + 1)), out.height) ||
-      !toUnsigned(s.substr(atPos + 1), out.refresh))
+      !LGParseRefreshRate(s.substr(atPos + 1), out.refreshMilliHz))
       return false;
 
   // sanity check
   if (out.width   < 640   ||
       out.height  < 480   ||
       out.width   > 16384 ||
-      out.height  > 16384 ||
-      out.refresh < 30    ||
-      out.refresh > 1000)
+      out.height  > 16384)
     return false;
 
   out.extraMode = false;