Excessive CPU load by the xorg-server and GUI's hard lags

[eshkrig]

Hi!
Sorry for my English.

I use vnc xorg-module for remote support users.

In September 2016 I have updated xorg-server, tigervnc, xf86-video-ati and related packages.

Packages versions before updating:
xorg-server-1.17.4
xf86-video-ati-7.5.0
tigervnc-1.4.2-r2

Packages versions after updating:
xorg-server-1.18.4
xf86-video-ati-7.7.0
tigervnc-1.6.0-r2

I faced the problem of excessive CPU load by the xorg-server and GUI's hard lags.
I found that disabling vnc module in xorg.conf eliminates the problem.

The problem occurs only with video cards AMD.

I recently noticed that the problem only occurs when monitor connected via DVI.
When monitor connected through VGA everything works as it should.

To date, kernel version 4.4.39, but different versions 4.4.6 - 4.4.39 have no effect on the problem.
I tried version xf86-video-ati-7.8.0 and tigervnc-1.7.0 - the problem persists.

Distribution - Gentoo.

The attached files Xorg.0.log, /proc/cpuinfo, output of dmesg, lspci, dmidecode.

attach.zip

[CendioOssman]

If it only happens on one port then it sounds like a problem in the video driver. Have you talked to the radeon developers and seen if they have some insight?

[eshkrig]

I added a bug report to xorg driver/radeon: https://bugs.freedesktop.org/show_bug.cgi?id=99457

[CendioOssman]

Great. I'll close this issue right now, but please comment if there turns out to be something we can do to improve the situation.

[eshkrig]

Please, reopen and see comment https://bugs.freedesktop.org/show_bug.cgi?id=99457#c30

[CendioOssman]

Please try 84c72fe and see if that fixes the issue for you.

[eshkrig]

Thank you. All works fine.
I am currently using version tigervnc-1.7.1. I was able to apply 84c72fe only after small changes:
diff -Naur tigervnc-1.7.1.orig/unix/xserver/hw/vnc/vncHooks.c tigervnc-1.7.1/unix/xserver/hw/vnc/vncHooks.c
--- tigervnc-1.7.1.orig/unix/xserver/hw/vnc/vncHooks.c 2017-01-18 15:39:28.000000000 +0300
+++ tigervnc-1.7.1/unix/xserver/hw/vnc/vncHooks.c 2017-02-13 17:22:20.854082779 +0300
@@ -1033,12 +1033,21 @@

// Unwrap and rewrap helpers

+#if XORG >= 116
+#define GC_OP_PROLOGUE(pGC, name)\
+ vncHooksGCPtr pGCPriv = vncHooksGCPrivate(pGC);\
+ const GCFuncs *oldFuncs = pGC->funcs;\
+ pGC->funcs = pGCPriv->wrappedFuncs;\
+ pGC->ops = pGCPriv->wrappedOps; \
+ DBGPRINT((stderr,"vncHooks" #name " called\n"))
+#else
#define GC_OP_PROLOGUE(pGC, name)\
vncHooksGCPtr pGCPriv = vncHooksGCPrivate(pGC);\
GCFuncs *oldFuncs = pGC->funcs;\
pGC->funcs = pGCPriv->wrappedFuncs;\
pGC->ops = pGCPriv->wrappedOps; \
DBGPRINT((stderr,"vncHooks" #name " called\n"))
+#endif

#define GC_OP_EPILOGUE(pGC)\
pGCPriv->wrappedOps = pGC->ops;\

[CendioOssman]

Great. Putting this on master then.