Black lstopo window

[rubin55]

What version of hwloc are you using?

# lstopo --version
lstopo 2.9.1

Which operating system and hardware are you running on?

# uname -a
Linux ORION 6.5.7-arch1-1 #1 SMP PREEMPT_DYNAMIC Tue, 10 Oct 2023 21:10:21 +0000 x86_64 GNU/Linux

# lstopo -
Machine (126GB total)
  Package L#0
    NUMANode L#0 (P#0 126GB)
    L3 L#0 (16MB)
      L2 L#0 (512KB) + L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0
        PU L#0 (P#0)
        PU L#1 (P#8)
      L2 L#1 (512KB) + L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1
        PU L#2 (P#1)
        PU L#3 (P#9)
      L2 L#2 (512KB) + L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2
        PU L#4 (P#2)
        PU L#5 (P#10)
      L2 L#3 (512KB) + L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3
        PU L#6 (P#3)
        PU L#7 (P#11)
    L3 L#1 (16MB)
      L2 L#4 (512KB) + L1d L#4 (32KB) + L1i L#4 (32KB) + Core L#4
        PU L#8 (P#4)
        PU L#9 (P#12)
      L2 L#5 (512KB) + L1d L#5 (32KB) + L1i L#5 (32KB) + Core L#5
        PU L#10 (P#5)
        PU L#11 (P#13)
      L2 L#6 (512KB) + L1d L#6 (32KB) + L1i L#6 (32KB) + Core L#6
        PU L#12 (P#6)
        PU L#13 (P#14)
      L2 L#7 (512KB) + L1d L#7 (32KB) + L1i L#7 (32KB) + Core L#7
        PU L#14 (P#7)
        PU L#15 (P#15)
  HostBridge
    PCIBridge
      PCI 01:00.0 (NVMExp)
        Block(Disk) "nvme0n1"
    PCIBridge
      PCI 02:00.1 (SATA)
        Block(Disk) "sdd"
        Block(Disk) "sdb"
        Block(Disk) "sdc"
        Block(Disk) "sda"
      PCIBridge
        PCIBridge
          PCI 04:00.0 (Ethernet)
            Net "eth0"
    PCIBridge
      PCIBridge
        PCIBridge
          PCI 0a:00.0 (VGA)
  Misc(MemoryModule)
  Misc(MemoryModule)
  Misc(MemoryModule)
  Misc(MemoryModule)

Details of the problem

• What happened?

Running lstopo produces a black window, see screenshot:

• How did you start your process?

I simply run lstopo from the commandline.

• How did it fail? Crash? Unexpected result?

It displays a black window instead of the GL-based overview of my system.

[bgoglin]

Oh, that's interesting. Random things to test:

• if the graphical output, try resize the window, pressing + or - to change zoom, etc
• Export to PNG with lstopo foo.pngand open that new foo.png. Is it black as well? If yes, that's a Cairo issue. If not, that's a Cairo/X11 only issue.
• Do you have some sort of black theme in your graphical environment or whatever that could lead to some colors being inverted and lstopo failing to adapt?
• Try lstopo --palette white and lstopo --palette grey in case they work better.
• Try to change the colors of one object by adding style attribute in the XML:

lstopo foo.xml
hwloc-annotate foo.xml foo.xml -- root -- info lstopoStyle "Background=#000000;Text=#ffffff"
lstopo -i foo.xml 

[rubin55]

Thanks for the pointers, here goes:

• Resizing, either by dragging or +/- does not change anything, window stays black
• Exporting to PNG works: the resulting image displays normally
• I don't have any theme customization going on (tried with default Gnome, both dark mode and light mode)
• The --palette options don't change anything, window stays black
• When changing the colors through foo.xml, the left-top title for the machine becomes readable (white text on black background)

Fwiw, I tested on three machines (all running the same version and same OS/kernel, two with AMD Radeon cards, one with Intel graphics). The radeons both display fully black screens, the intel displays this:

[bgoglin]

What cairo version do you have? Do you know if things worked better on these systems in the past?

[rubin55]

These systems use cairo 1.18.0 currently. I do know that these systems all had lstopo working normally before.

[bgoglin]

Thanks, ok I am going to upgrade my cairo on several systems to try to reproduce.

[bgoglin]

In the meantime, you could try to comment-out this line in the source since it sets the drawing color to black. We're supposed to only draw the border of the box with this color, but maybe we end up filling the box some reason.

--- a/utils/lstopo/lstopo-cairo.c
+++ b/utils/lstopo/lstopo-cairo.c
@@ -73,7 +73,7 @@ topo_cairo_box(struct lstopo_output *loutput, const struct lstopo_color *lcolor,
   cairo_fill(c);
 
   cairo_rectangle(c, x, y, width, height);
-  cairo_set_source_rgb(c, 0, 0, 0);
+//  cairo_set_source_rgb(c, 0, 0, 0);
 
   if (cpukind_style) {
     double dash = (double)(1U << cpukind_style);

Boxes won't have border anymore, but hopefully they'll have the expected background.

Another random patch to try is this one in case your compiler decides to cast to float after dividing:

--- a/utils/lstopo/lstopo-cairo.c
+++ b/utils/lstopo/lstopo-cairo.c
@@ -69,7 +69,7 @@ topo_cairo_box(struct lstopo_output *loutput, const struct lstopo_color *lcolor,
   int r = lcolor->r, g = lcolor->g, b = lcolor->b;
 
   cairo_rectangle(c, x, y, width, height);
-  cairo_set_source_rgb(c, (float)r / 255, (float) g / 255, (float) b / 255);
+  cairo_set_source_rgb(c, ((float)r) / 255, ((float)g) / 255, ((float)b) / 255);
   cairo_fill(c);
 
   cairo_rectangle(c, x, y, width, height);