[Openchrome-devel] Some fixes for VX800 in kms-branch

Thomas Schlichter thomas.schlichter
Wed Nov 2 05:00:48 PDT 2011

Dear James,

thank you for your work of extending and actualizing the openchrome driver and 
the via drm kernel module. I'm currently testing the new openchrome driver 
(revision 1020) without any drm kernel module on my Samsung NC20 (VIA VX800 
chipset). To be able to use it successfully, I am using the attached small 
patch which I want to share with you.

It contains following (small) modifications:
1. Remove "static" from VIAFreeRec()
   The function VIAFreeRec() is used in several C-Files, so it should not be
2. Remove "Bool ret" from VIAEnterVT()
   The return value "ret" is never assigned, so depending on the old stack
   contents, the function VIAEnterVT() may return FALSE accidently.
3. Directly use VIALeaveVT() in VIACloseScreen()
   I get a NULL-pointer dereference in VIACloseScreen() without this change.
   Maybe the function pointer is already set to NULL when VIACloseScreen() is
   called? Unfortunately here I don't exactly know why the current code does
   not work... ;-(
4. Remove call to VIAUnmapMem() in VIACloseScreen()
   If this function would be called, a subsequent VIAScreenInit() crashes.
   This happens on KDE logout without having "TerminateServer" set in kdmrc.
5. Do not call via_dp_init() in ViaOutputsDetect() for VX800
   Without this change, Xorg would hang on startup.

I think at least modification 1, 2, and 4 are correct fixes, whereas 
modifications 3 and 5 may just be workarounds for deeper problems I didn't 

Hopefully this may help you to further improve the openchrome driver.

Kind regards,
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