eglfs/kms: Re-enable drm/gbm format overrides in the config file

Follow up to 091a386eaf91ad8932332a8aefc2df793de59f6c

Defaulting to querying from the egl config is fine, but dropping support
for the "format" key in the output list in the json config file is not
ideal.

Task-number: QTBUG-76748
Change-Id: I25dc99369d118c300cdef25b464426f6be85453b
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

1 files changed, 25 insertions, 12 deletions

diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
index 24f82e7843..3a2951efbd 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
@@ -155,20 +155,33 @@ gbm_surface *QEglFSKmsGbmScreen::createSurface(EGLConfig eglConfig)
         qCDebug(qLcEglfsKmsDebug, "Creating gbm_surface for screen %s", qPrintable(name()));
 
         const auto gbmDevice = static_cast<QEglFSKmsGbmDevice *>(device())->gbmDevice();
-        EGLint native_format = -1;
-        EGLBoolean success = eglGetConfigAttrib(display(), eglConfig, EGL_NATIVE_VISUAL_ID, &native_format);
-        qCDebug(qLcEglfsKmsDebug) << "Got native format" << hex << native_format << dec << "from eglGetConfigAttrib() with return code" << bool(success);
-
-        if (success)
-            m_gbm_surface = gbm_surface_create(gbmDevice,
-                                           rawGeometry().width(),
-                                           rawGeometry().height(),
-                                           native_format,
-                                           GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
+        // If there was no format override given in the config file,
+        // query the native (here, gbm) format from the EGL config.
+        const bool queryFromEgl = !m_output.drm_format_requested_by_user;
+        if (queryFromEgl) {
+            EGLint native_format = -1;
+            EGLBoolean success = eglGetConfigAttrib(display(), eglConfig, EGL_NATIVE_VISUAL_ID, &native_format);
+            qCDebug(qLcEglfsKmsDebug) << "Got native format" << hex << native_format << dec
+                                      << "from eglGetConfigAttrib() with return code" << bool(success);
+
+            if (success) {
+                m_gbm_surface = gbm_surface_create(gbmDevice,
+                                                   rawGeometry().width(),
+                                                   rawGeometry().height(),
+                                                   native_format,
+                                                   GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
+                if (m_gbm_surface)
+                    m_output.drm_format = gbmFormatToDrmFormat(native_format);
+            }
+        }
 
-        if (!m_gbm_surface) { // fallback for older drivers
+        // Fallback for older drivers, and when "format" is explicitly specified
+        // in the output config. (not guaranteed that the requested format works
+        // of course, but do what we are told to)
+        if (!m_gbm_surface) {
             uint32_t gbmFormat = drmFormatToGbmFormat(m_output.drm_format);
-            qCDebug(qLcEglfsKmsDebug, "Could not create surface with EGL_NATIVE_VISUAL_ID, falling back to format %x", gbmFormat);
+            if (queryFromEgl)
+                qCDebug(qLcEglfsKmsDebug, "Could not create surface with EGL_NATIVE_VISUAL_ID, falling back to format %x", gbmFormat);
             m_gbm_surface = gbm_surface_create(gbmDevice,
                                            rawGeometry().width(),
                                            rawGeometry().height(),