Details
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Bug
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Resolution: Unresolved
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P2: Important
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None
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5.9.4
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None
Description
Hello
I am using Qt 5.9.3/5.9.4 port for Nvidia Tegra Linux x64.
There was one case here, Qt Linux applications were crashing without any message except 'segmentation fault'. It was very time-consuming to finally discover that this happens when in /etc/qt.eglfs.kms.conf HDMI1 the display is set to off, when it has to be on. It was set on system level Qt to use the KMS configuration:
export QT_QPA_EGLFS_KMS_CONFIG=/etc/qt.eglfs.kms.conf
The content of this file is:
vi /etc/qt.eglfs.kms.conf
{"outputs":[
{"name":"HDMI1","mode":"off"}
,
{"name":"HDMI2","mode":"1920x720"}
]}
When the conf file is not used at all (without the export) or when I fix it to use HDMI1 QT applications are running Ok, otherwise are just crashing with 'Segmentation Fault' error. So my question is- why not add some print in KMS plugin, like - 'Display not found, see /etc/qt.eglfs.kms.conf"? Only after enabling the QT logs (QT_QPA_EGLFS_DEBUG and QT_LOGGING_RULES) I was able to see some logs suggesting that the problem is in qt.eglfs.kms.conf. The complete logs are:
[DBG | qt.qpa.eglfs.kms] Loading KMS setup from "/etc/qt.eglfs.kms.conf" [qkmsdevice.cpp:553]
[DBG | qt.qpa.eglfs.kms] Requested configuration (some settings may be ignored):
hwcursor: true
pbuffers: false
separateScreens: false
virtualDesktopLayout: 0
outputs: QMap(("HDMI1", QMap(("mode", QVariant(QString, "off"))("name", QVariant(QString, "HDMI1"))))("HDMI2", QMap(("mode", QVariant(QString, "1920x720"))("name", QVariant(QString, "HDMI2"))))) ]
[DBG | qt.qpa.eglfs.kms] New DRM/KMS on EGLDevice integration created [qeglfskmsegldeviceintegration.cpp:56]
[DBG | qt.qpa.eglfs.kms] platformInit: Opening DRM device [qeglfskmsintegration.cpp:70]
[DBG | qt.qpa.eglfs.kms] Found 1 EGL devices [qeglfskmsegldeviceintegration.cpp:278]
[DBG | qt.qpa.eglfs.kms] Using backend-provided DRM device drm-nvdc [qkmsdevice.cpp:398]
DEBUG: libnvdc will contact display server at ip=10.0.0.2
DEBUG: Display Client is in VM 1
DEBUG: Server is running in VM 0
[DBG | qt.qpa.eglfs.kms] Creating display [qeglfskmsegldeviceintegration.cpp:73]
nvrm_gpu: Bug[ 2474.337043] audit: type=1701 audit(1520353343.936:30): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=6252 comm="appman" exe="/opt/qt-5.9/bin/appman" sig=6
200215060 workaround enabled.
[DBG | qt.qpa.eglfs.kms] Turning off output "HDMI1" [qkmsdevice.cpp:214]
[DBG | qt.qpa.eglfs.kms] Sorted screen list: QVector() [qkmsdevice.cpp:472]
This is followed by application "segmentation fault'.
Thanks.