Bug#1107294: libqt5core5a: Qt-based applications fail to run, due to incorrect screen metrics

[Adam Chyła]

Package: libqt5core5a
Version: 5.15.8+dfsg-11+deb12u3
Severity: normal
Tags: patch upstream
X-Debbugs-Cc: a...@chyla.org


Dear Maintainer,

The Qt-based applications fail to run. All the apps hang without displaying
anything on the screen, then terminate.


can be used as a workaround for the issue.


As an example, let me take the qtop application:

  $ qtop

  Killed



usage are increasing:


  Current time: 08:38:44

  adam       83283  1.7  0.0  46408  2344 pts/13   D+   08:38   0:00 qtop
  Current time: 08:38:45

  adam       83283  2.3  0.1  81480 12152 pts/13   D+   08:38   0:00 qtop
  Current time: 08:38:47

  adam       83283  2.4  0.2 164676 23068 pts/13   Dl+  08:38   0:00 qtop
  Current time: 08:38:48

  adam       83283  4.0  0.4 333088 35260 pts/13   Dl+  08:38   0:00 qtop
  [..]
  Current time: 08:41:50

  adam       83283 90.8  1.4 736760 118352 pts/13  Rl+  08:38   2:49 qtop
  Current time: 08:41:51

  adam       83283 90.9  1.4 736760 118352 pts/13  Rl+  08:38   2:50 qtop
  Current time: 08:41:52

  adam       83283 90.9  1.4 736760 118352 pts/13  Rl+  08:38   2:51 qtop
  Current time: 08:41:53

  adam       83283 91.0 13.6 5004544 1091248 pts/13 Rl+ 08:38   2:52 qtop


Finally, the qtop is terminated by the kernel due to an Out of Memory (OOM):

  $ dmesg
  [...]

  [122338.523477] Call Trace:
  [122338.523481]  <TASK>
  [122338.523484]  dump_stack_lvl+0x44/0x5c
  [122338.523492]  dump_header+0x4c/0x22b
  [122338.523498]  oom_kill_process.cold+0xb/0x10
  [122338.523503]  out_of_memory+0x1fd/0x4c0
  [...]
  [122338.523577] RIP: 0033:0x7f04297e921f
  [122338.523583] Code: Unable to access opcode bytes at 0x7f04297e91f5.
  [122338.523585] RSP: 002b:00007f04281fea90 EFLAGS: 00010293

  [122338.523600]  </TASK>
  [122338.523601] Mem-Info:
  [122338.523603] active_anon:223303 inactive_anon:1606798 isolated_anon:0
                   active_file:106 inactive_file:17 isolated_file:0
                   unevictable:44733 dirty:1 writeback:3
                   slab_reclaimable:23415 slab_unreclaimable:28840
                   mapped:735444 shmem:880311 pagetables:15846
                   sec_pagetables:0 bounce:0
                   kernel_misc_reclaimable:0
                   free:26608 free_pcp:124 free_cma:0

  [122338.523625] lowmem_reserve[]: 0 2741 7708 7708 7708

  [122338.523637] lowmem_reserve[]: 0 0 4967 4967 4967

  [122338.523649] lowmem_reserve[]: 0 0 0 0 0

  [122338.523714] 895623 total pagecache pages
  [122338.523715] 15054 pages in swap cache
  [122338.523717] Free swap  = 0kB
  [122338.523718] Total swap = 999420kB
  [122338.523719] 2063578 pages RAM
  [122338.523720] 0 pages HighMem/MovableOnly
  [122338.523721] 64437 pages reserved
  [122338.523722] 0 pages hwpoisoned
  [122338.523723] Tasks state (memory values in pages):

  [...]

  [...]




functions:


      at ./src/fcmatch.c:1082

      at fontconfig/qfontconfigdatabase.cpp:716

      foundry=<optimized out>) at text/qfontdatabase.cpp:1020

      at text/qfontengine.cpp:1843

      at text/qfontengine.cpp:1822

  [..]


After running the qtop with GDB, analyzing the stack trace along with
the related code, it turned out that the Qt library failed to get the glyph,
resulting in the loading of the next available font. This led to the loading
of all available system fonts.

That behavior was caused by an invalid pixelSize value


  (gdb) break qfontdatabase.cpp:936
  (gdb) run
  [..]
  945     in text/qfontdatabase.cpp
  (gdb) p /d pixelSize
  $2 = 65535
  [..]
  950     in text/qfontdatabase.cpp
  (gdb) p /d pixelSize
  $3 = -298261618




  qtbase-everywhere-src-5.15.8/src/gui/text/qfontdatabase.cpp
  934 static
  935 QFontEngine *loadSingleEngine(int script,
  936                               const QFontDef &request,

  938                               QtFontStyle *style, QtFontSize *size)
  939 {
  940     Q_UNUSED(foundry);
  941
  942     Q_ASSERT(size);

  944     int pixelSize = size->pixelSize;

  946         || pfdb->fontsAlwaysScalable()) {
  947         pixelSize = request.pixelSize;
  948     }
  949
  950     QFontDef def = request;
  951     def.pixelSize = pixelSize;


The request.pixelSize was set in QFontDatabase::load function:

  qtbase-everywhere-src-5.15.8/src/gui/text/qfontdatabase.cpp
  2804 void QFontDatabase::load(const QFontPrivate *d, int script)
  2805 {
  2806     QFontDef req = d->request;
  2807
  2808     if (req.pixelSize == -1) {

  2810         req.pixelSize = qRound(req.pixelSize);
  2811     }
  2812     if (req.pointSize < 0)
  2813         req.pointSize = req.pixelSize*72.0/d->dpi;


Let me focus on d->dpi (line 200, 196, 188):

  qtbase-everywhere-src-5.15.8/src/gui/text/qfont.cpp
  179 Q_GUI_EXPORT int qt_defaultDpiY()
  180 {
  181     if (QCoreApplication::instance()->testAttribute(Qt::AA_Use96Dpi))
  182         return 96;
  183
  184     if (!qt_is_gui_used)
  185         return 75;
  186
  187     if (const QScreen *screen = QGuiApplication::primaryScreen())
  188         return qRound(screen->logicalDotsPerInchY());
  189

  191     return 100;
  192 }
  193
  194 Q_GUI_EXPORT int qt_defaultDpi()
  195 {
  196     return qt_defaultDpiY();
  197 }
  198
  199 QFontPrivate::QFontPrivate()
  200     : engineData(nullptr), dpi(qt_defaultDpi()),

  202       capital(0), letterSpacingIsAbsolute(false), scFont(nullptr)
  203 {
  204 }


It was set to the value returned from screen->logicalDotsPerInchY():

  qtbase-everywhere-src-5.15.8/src/gui/kernel/qscreen.cpp
  329 qreal QScreen::logicalDotsPerInchY() const
  330 {
  331     Q_D(const QScreen);
  332     if (QHighDpiScaling::isActive())
  333         return QHighDpiScaling::logicalDpi(this).second;
  334     return d->logicalDpi.second;
  335 }


In my case, d->logicalDpi.second was returned. logicalDpi is set
in QScreenPrivate::setPlatformScreen function (line 114):

  qtbase-everywhere-src-5.15.8/src/gui/kernel/qscreen.cpp
  73 QScreen::QScreen(QPlatformScreen *screen)
  74     : QObject(*new QScreenPrivate(), nullptr)
  75 {
  76     Q_D(QScreen);
  77     d->setPlatformScreen(screen);
  78 }

  qtbase-everywhere-src-5.15.8/src/gui/kernel/qscreen.cpp
  107 void QScreenPrivate::setPlatformScreen(QPlatformScreen *screen)
  108 {
  109     Q_Q(QScreen);
  110     platformScreen = screen;
  111     platformScreen->d_func()->screen = q;
  112     orientation = platformScreen->orientation();
  113

  115
  116     refreshRate = platformScreen->refreshRate();
  117     // safeguard ourselves against buggy platform behavior...
  118     if (refreshRate < 1.0)
  119         refreshRate = 60.0;



to a positive value, this can be used to workaround the issue:

  qtbase-everywhere-src-5.15.8/src/gui/kernel/qplatformscreen.cpp
  198 // Helper function for accessing the platform screen logical dpi
  199 // which accounts for QT_FONT_DPI.

  201 {

  203     return overrideDpi > 0 ?  QDpi(overrideDpi, overrideDpi) : in;
  204 }



function:

qtbase-everywhere-src-5.15.8/src/plugins/platforms/xcb/qxcbscreen.cpp
  720 int QXcbScreen::forcedDpi() const
  721 {
  722     const int forcedDpi = m_virtualDesktop->forcedDpi();
  723     if (forcedDpi > 0)
  724         return forcedDpi;
  725     return 0;
  726 }
  727
  728 QDpi QXcbScreen::logicalDpi() const
  729 {
  730     const int forcedDpi = this->forcedDpi();
  731     if (forcedDpi > 0)
  732         return QDpi(forcedDpi, forcedDpi);
  733
  734     // Fall back to physical virtual desktop DPI, but prevent
  735     // using DPI values lower than 96. This ensuers that connecting
  736     // to e.g. a TV works somewhat predictabilly.
  737     QDpi virtualDesktopPhysicalDPi = m_virtualDesktop->dpi();
  738     return QDpi(std::max(virtualDesktopPhysicalDPi.first, 96.0),
  739                 std::max(virtualDesktopPhysicalDPi.second, 96.0));
  740 }


The code above returns the {96, inf} pair, so need to focus
on the virtualDesktopPhysicalDPi values:

  (gdb) break QXcbScreen::logicalDpi
  (gdb) run

  (gdb) next
  731     in ./src/plugins/platforms/xcb/qxcbscreen.cpp
  (gdb) print forcedDpi
  $1 = 0
  (gdb) next

  737     in ./src/plugins/platforms/xcb/qxcbscreen.cpp
  (gdb) next
  738     in ./src/plugins/platforms/xcb/qxcbscreen.cpp
  (gdb) next

  (gdb) next

  116     kernel/qscreen.cpp: Nie ma takiego pliku ani katalogu.
  (gdb) print logicalDpi
  $4 = {first = 96, second = inf}


virtualDesktopPhysicalDPi is calculated in QXcbVirtualDesktop::dpi function:

qtbase-everywhere-src-5.15.8/src/plugins/platforms/xcb/qxcbscreen.cpp
  135 QDpi QXcbVirtualDesktop::dpi() const
  136 {
  137     const QSize virtualSize = size();
  138     const QSize virtualSizeMillimeters = physicalSize();
  139

  142 }


size, physicalSize are as follows:

qtbase-everywhere-src-5.15.8/src/plugins/platforms/xcb/qxcbscreen.h



Checking with GDB, *_in_pixels looks correct, but *_in_millimeters appears
to be incorrect:

  (gdb) print /d m_screen->width_in_pixels
  $2 = 4310
  (gdb) print /d m_screen->height_in_pixels
  $3 = 1080
  (gdb) print /d m_screen->width_in_millimeters
  $4 = 0
  (gdb) print /d m_screen->height_in_millimeters
  $5 = 0


These values are used in the nominative within the QXcbVirtualDesktop::dpi
function, so in qxcbscreen.cpp:140 there is division by 0.

width_in_millimeters, height_in_millimeters are members of the xcb_screen_t
structure from the libxcb. These variables are initialized by functions
from the mentioned library.

I'm uncertain if zeros are the correct values. The X Window System Protocol
specification doesn't mention anything about it: "Width-in-millimeters
and height-in-millimeters can be used to determine the physical size
and the aspect ratio" [1]. Based on this, zeros may be the correct values.
On the other hand, the X Resize, Rotate and Reflect Extension specification
provides some guidance, in which it states (RRSetScreenSize)
'width-in-millimeters' and 'height-in-millimeters' can be set to reflect
the physical size of the screen reported both through this extension
and the core protocol. They must be non-zero, or Value error results. [2]
This may require further investigation under separate bug report.

I believe the root cause of the issue is not in the Qt itself, however,
in my opinion Qt should handle the values appropriately. This can be done
in QXcbVirtualDesktop::dpi, by returning a default value in case of zeros
in the nominative.

Suggested patch that resolves the issue:


@@ -137,8 +137,12 @@
     const QSize virtualSize = size();
     const QSize virtualSizeMillimeters = physicalSize();


+
+    const int defaultDpi = 100;
+    return QDpi(defaultDpi, defaultDpi);
 }

 QXcbScreen *QXcbVirtualDesktop::screenAt(const QPoint &pos) const


Best regards,
Adam.


[1] https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html
[2] https://www.x.org/releases/X11R7.7/doc/randrproto/randrproto.txt


-- System Information:
Debian Release: 12.11
  APT prefers stable-updates

Architecture: amd64 (x86_64)

Kernel: Linux 6.1.0-37-amd64 (SMP w/8 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE

Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages libqt5core5a depends on:
ii  libc6                  2.36-9+deb12u10
ii  libdouble-conversion3  3.2.1-1
ii  libgcc-s1              12.2.0-14+deb12u1
ii  libglib2.0-0           2.74.6-2+deb12u6
ii  libicu72               72.1-3
ii  libpcre2-16-0          10.42-1
ii  libstdc++6             12.2.0-14+deb12u1
ii  libzstd1               1.5.4+dfsg2-5
ii  shared-mime-info       2.2-1
ii  zlib1g                 1:1.2.13.dfsg-1

Versions of packages libqt5core5a recommends:
ii  qttranslations5-l10n  5.15.8-2

Versions of packages libqt5core5a suggests:
ii  libthai0  0.1.29-1

-- no debconf information

Setting the QT_FONT_DPI environment variable to a sensible default, such as 100,   ErrorHandler::Throw - warning: Setting a QCompleter on non-editable QComboBox is not allowed. file:  line: 0 function:   ErrorHandler::Throw - warning: Setting a QCompleter on non-editable QComboBox is not allowed. file:  line: 0 function:   ErrorHandler::Throw - warning: QWidget::setMinimumSize: (/MainWindow) The largest allowed size is (16777215,16777215) file: line: 0 function:   ErrorHandler::Throw - warning: QWidget::setMinimumSize: (/MainWindow) The largest allowed size is (16777215,16777215) file: line: 0 function:   ErrorHandler::Throw - warning: QWidget::setMinimumSize: (/MainWindow) The largest allowed size is (16777215,16777215) file: line: 0 function:   ErrorHandler::Throw - warning: QWidget::setMinimumSize: (/MainWindow) The largest allowed size is (16777215,16777215) file: line: 0 function: Looking at the ps output while the app is running, both the CPU time and memory   $ while true ; do LC_ALL=C date "+Current time: %H:%M:%S" ; ps -C qtop Hu ; sleep 1 ; done   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND   [122338.523460] gmain invoked oom-killer: gfp_mask=0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), order=0, oom_score_adj=0   [122338.523471] CPU: 4 PID: 5110 Comm: gmain Tainted: G OE      6.1.0-33-amd64 #1  Debian 6.1.133-1   [122338.523475] Hardware name: LENOVO 20184/INVALID, BIOS 5ECN96WW(V9.01) 03/14/2013   [122338.523588] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 00007f04297e921f   [122338.523590] RDX: 0000000000000f9c RSI: 0000000000000002 RDI: 000055dc4f759490   [122338.523592] RBP: 000055dc4f7f0a80 R08: 0000000000000000 R09: 00007f0429a042c0   [122338.523593] R10: 00007ffd2b881080 R11: 0000000000000293 R12: 000055dc4f759490   [122338.523595] R13: 00007f0429932150 R14: 0000000000000f9c R15: 0000000000000002   [122338.523610] Node 0 active_anon:893212kB inactive_anon:6427192kB active_file:424kB inactive_file:68kB unevictable:178932kB isolated(anon):0kB isolated(file):0kB mapped:2941776kB dirty:4kB writeback:12kB shmem:3521244kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 1347584kB writeback_tmp:0kB kernel_stack:25616kB pagetables:63384kB sec_pagetables:0kB all_unreclaimable? no   [122338.523618] Node 0 DMA free:14336kB boost:0kB min:128kB low:160kB high:192kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15984kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB   [122338.523630] Node 0 DMA32 free:43580kB boost:0kB min:23984kB low:29980kB high:35976kB reserved_highatomic:0KB active_anon:122436kB inactive_anon:2684992kB active_file:0kB inactive_file:0kB unevictable:6680kB writepending:0kB present:3005688kB managed:2894900kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB   [122338.523642] Node 0 Normal free:48516kB boost:0kB min:43464kB low:54328kB high:65192kB reserved_highatomic:4096KB active_anon:770776kB inactive_anon:3742140kB active_file:744kB inactive_file:68kB unevictable:172252kB writepending:472kB present:5232640kB managed:5086304kB mlocked:192kB bounce:0kB free_pcp:496kB local_pcp:0kB free_cma:0kB   [122338.523653] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 3*4096kB (M) = 14336kB   [122338.523669] Node 0 DMA32: 329*4kB (UME) 369*8kB (UME) 292*16kB (UME) 288*32kB (UME) 157*64kB (UME) 68*128kB (UME) 25*256kB (UE) 1*512kB (U) 0*1024kB 0*2048kB 0*4096kB = 43820kB   [122338.523690] Node 0 Normal: 1059*4kB (UME) 824*8kB (UME) 631*16kB (UME) 249*32kB (UME) 138*64kB (UME) 57*128kB (UME) 8*256kB (ME) 2*512kB (M) 0*1024kB 0*2048kB 0*4096kB = 48092kB   [122338.523711] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB   [122338.523725] [  pid  ]   uid  tgid total_vm      rss pgtables_bytes swapents oom_score_adj name   [122338.524391] [  83283]  1000 83283  1251136   730206 6475776        0           200 qtop   [122338.524399] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/vte-spawn-bd2dd4b4-bc66-4aec-a8d9-673ffe016ce3.scope,task=qtop,pid=83283,uid=1000   [122338.524441] Out of memory: Killed process 83283 (qtop) total-vm:5004544kB, anon-rss:27264kB, file-rss:0kB, shmem-rss:2893560kB, UID:1000 pgtables:6324kB oom_score_adj:200 I have collected the core dump and the stack trace points to the font related   #0  0x00007f275c5f845d in FcCompare (pat=pat@entry=0x55a04f0a7750, fnt=0x7f274beb3840, value=value@entry=0x7ffc770f0d50,       result=result@entry=0x7ffc770f0fcc, data=data@entry=0x7ffc770f0d48) at ./src/fcmatch.c:617   #1  0x00007f275c5f886e in FcFontSetMatchInternal (sets=sets@entry=0x7ffc770f0f50, nsets=<optimized out>,       p=p@entry=0x55a04f0a7750, result=result@entry=0x7ffc770f0fcc) at ./src/fcmatch.c:896   #2  0x00007f275c5f9917 in IA__FcFontMatch (config=0x55a04ef3cc10, p=0x55a04f0a7750, result=0x7ffc770f0fcc)   #3  0x00007f275c164894 in QFontconfigDatabase::setupFontEngine (this=this@entry=0x7f27540077b0,       engine=engine@entry=0x55a04eee6a90, fontDef=...) at fontconfig/qfontconfigdatabase.cpp:980   #4  0x00007f275c1650a5 in QFontconfigDatabase::fontEngine (this=0x7f27540077b0, f=..., usrPtr=<optimized out>)   #5  0x00007f2760227421 in loadSingleEngine (foundry=<optimized out>, size=<optimized out>, style=<optimized out>,       family=<optimized out>, request=..., script=<optimized out>) at text/qfontdatabase.cpp:990   #6  loadEngine (script=script@entry=2, request=..., family=0x55a04f337b10, style=0x55a04f337be0, size=0x55a04f337c10,   #7  0x00007f2760227f23 in QFontDatabase::findFont (request=..., script=script@entry=2,       preferScriptOverFamily=preferScriptOverFamily@entry=false) at text/qfontdatabase.cpp:2784   #8  0x00007f276020f97c in QFontEngineMulti::loadEngine (this=<optimized out>, at=<optimized out>)   #9  0x00007f276021069f in QFontEngineMulti::ensureEngineAt (this=this@entry=0x55a04ec02f20, at=at@entry=22)   #10 0x00007f2760210da3 in QFontEngineMulti::stringToCMap (this=0x55a04ec02f20, str=<optimized out>, len=<optimized out>,       glyphs=<optimized out>, nglyphs=0x7ffc770f163c, flags=...) at text/qfontengine.cpp:1935 in the qtbase-everywhere-src-5.15.8/src/gui/text/qfontdatabase.cpp, line 950: The if statement (lines 945-948) changed the initial value to a negative value:   937                               QtFontFamily *family, QtFontFoundry *foundry,   943     QPlatformFontDatabase *pfdb = QGuiApplicationPrivate::platformIntegration()->fontDatabase();   945     if (!pixelSize || (style->smoothScalable && pixelSize == SMOOTH_SCALABLE)   2809         req.pixelSize = std::floor(((req.pointSize * d->dpi) / 72) * 100 + 0.5) / 100;   190     //PI has not been initialised, or it is being initialised. Give a default dpi   201       underline(false), overline(false), strikeOut(false), kerning(true),   114     logicalDpi = QPlatformScreen::overrideDpi(platformScreen->logicalDpi()); The logicalDpi can be overwritten by setting the QT_FONT_DPI environment variable   200 QPair<qreal, qreal> QPlatformScreen::overrideDpi(const QPair<qreal, qreal> &in)   202     static const int overrideDpi = qEnvironmentVariableIntValue("QT_FONT_DPI"); For this particular case, the platformScreen->logicalDpi() code calls the QXcbScreen::logicalDpi   Thread 1 "qtop" hit Breakpoint 1.1, QXcbScreen::logicalDpi (this=0x55555595ffe0) at ./src/plugins/platforms/xcb/qxcbscreen.cpp:730   730     ./src/plugins/platforms/xcb/qxcbscreen.cpp: Nie ma takiego pliku ani katalogu.   Thread 1 "qtop" hit Breakpoint 1.2, QXcbScreen::logicalDpi (this=<optimized out>) at ./src/plugins/platforms/xcb/qxcbscreen.cpp:737   QXcbScreen::logicalDpi (this=0x55555595ffe0) at ../../../../include/QtCore/../../src/corelib/tools/qpair.h:58   58 ../../../../include/QtCore/../../src/corelib/tools/qpair.h: Nie ma takiego pliku ani katalogu.   QScreenPrivate::setPlatformScreen (this=0x7fffec003f50, screen=screen@entry=0x55555595ffe0) at kernel/qscreen.cpp:116   140     return QDpi(Q_MM_PER_INCH * virtualSize.width() / virtualSizeMillimeters.width(),   141                 Q_MM_PER_INCH * virtualSize.height() / virtualSizeMillimeters.height());   75     QSize size() const { return QSize(m_screen->width_in_pixels, m_screen->height_in_pixels); }   76     QSize physicalSize() const { return QSize(m_screen->width_in_millimeters, m_screen->height_in_millimeters); } --- a/src/plugins/platforms/xcb/qxcbscreen.cpp  2022-11-11 07:29:17.000000000 +0000 +++ b/src/plugins/platforms/xcb/qxcbscreen.cpp  2025-06-03 20:09:52.619026981 +0000 -    return QDpi(Q_MM_PER_INCH * virtualSize.width() / virtualSizeMillimeters.width(), -                Q_MM_PER_INCH * virtualSize.height() / virtualSizeMillimeters.height()); +    if (virtualSizeMillimeters.width() > 0 && virtualSizeMillimeters.height() > 0) +        return QDpi(Q_MM_PER_INCH * virtualSize.width() / virtualSizeMillimeters.width(), +                    Q_MM_PER_INCH * virtualSize.height() / virtualSizeMillimeters.height());   APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable-debug'), (500, 'stable') Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8), LANGUAGE not set

OpenPGP_signature.asc
Description: OpenPGP digital signature