I came across a commercial application which tries to set a really large application icon (2100×1500 pixels). This leads to an X11 error with KWin: > X Error of failed request: BadLength (poly request too large or internal Xlib length error) > Major opcode of failed request: 146 () > Minor opcode of failed request: 74 > Serial number of failed request: 168 > Current serial number in output stream: 168 With xtrace (and setting LIBGL_DRI3_DISABLE=true, without this xtrace was stuck before logging the error) I was able to dig out the following failing request: > 003:<: Warning: buffer filled! > 003:<: Warning: Waiting for rest of package (yet got 65524 of 17640036)! >003:<: Warning: buffer filled! >003:<:009d:17640036: Request(18): ChangeProperty mode=Replace(0x00) >window=0x07400005 property=0x152("_NET_WM_ICON") type=0x6("CARDINAL") data=0x00000834,0x00000834,0x00000000,0x0000000,[...] Manually scaling the window icon file down, let me start the application. Now, according to https://specifications.freedesktop.org/wm-spec/latest/ar01s05.html#idm139870829941264 it is the window managers job to scale the image down and that no maximum size is mandated by the spec for _NET_WM_ICON. This seems to indicate to me, that an application is actually free to set such a ridiculously large icon and the window manager should just scale it down. [NB: I can trigger this bug also with the Windows version of the application, if I run it through Wine. This seems to indicate, that Wine isn't scaling the image down either and also expects the window manager to deal with it.] Let me know if you need anything else.
Is xprop able to retrieve the icon
(In reply to Martin Flöser from comment #1) > Is xprop able to retrieve the icon I think I'm not following you: wouldn't I need a running application/window for xprop to work? With the shipped (large) icon file the application is not starting. I can just see the window border for a split second and then the application dies with that X error. Or do you mean "can xprop retrieve the manually scaled down icon"?
Oh it's the application giving this error? That changes everything: the window manager cannot trigger this issue. This is an application bug.