Bug 215155 - glBlendFunc() segfaults on R300
Summary: glBlendFunc() segfaults on R300
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: mesa
Version: 6
Hardware: i386
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Adam Jackson
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2006-11-11 17:20 UTC by Nick Lamb
Modified: 2008-05-01 15:38 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2006-11-14 20:13:26 UTC
Type: ---
Embargoed:


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Description Nick Lamb 2006-11-11 17:20:53 UTC
Description of problem:
I have a Radeon Mobility X600, and when I try to run software which calls
glBlendFunc() it crashes with a segfault. I don't have any other hardware
accelerated 3D hardware that works well enough to test this, so it might be 
specific to the R300 driver but I can't prove it.

In my own software I can work around this bug by removing calls to glBlendFunc()
although of course this means I no longer have transparency, which makes things
look very ugly.

Version-Release number of selected component (if applicable):
mesa-libGL-6.5.1-7.fc6

How reproducible:
Completely reproducible, happens every time. May need specific hardware to
reproduce if it's only this particular driver.

Steps to Reproduce:
1. Build or install software which uses glBlendFunc() such as the Mesa Teapot demo
2. Run it on FC6

Actual results:
Segfault

Expected results:
Working GL transparency support as per OpenGL specification

Additional info:

Here's an example backtrace from the GL Teapot example which I compiled from the
Mesa source used for FC6. Other applications, whether my own or third party
crash with a similar trace
[ ie _mesa_BlendFunc() calls _mesa_loopback_init_api_table() and then we crash ]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1208289584 (LWP 3710)]
0x002739a1 in _mesa_loopback_init_api_table () from /usr/lib/dri/r300_dri.so
(gdb) bt
#0  0x002739a1 in _mesa_loopback_init_api_table () from /usr/lib/dri/r300_dri.so
#1  0x0027eb44 in _mesa_BlendFunc () from /usr/lib/dri/r300_dri.so
#2  0x08049bb5 in main (ac=1, av=0xbfa0d9c4) at teapot.c:655

Comment 1 Nick Lamb 2006-11-14 20:13:26 UTC
Sorry, bug was caused by a stale build environment from some tests I ran before
upgrading to FC6. Not a Fedore Core bug, thus closing NOTABUG.


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