Bug 12872

Summary:	pwc mmap always fails with EAGAIN
Product:	Drivers	Reporter:	Rafael J. Wysocki (rjw)
Component:	Other	Assignee:	drivers_other
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	avillaci, fdziarmagowski, suresh.b.siddha, venki
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.29-rc8	Subsystem:
Regression:	Yes	Bisected commit-id:
Bug Depends on:
Bug Blocks:	12398

Description Rafael J. Wysocki 2009-03-14 12:02:41 UTC

Subject    : REGRESSION: 2.6.28.7 => 2.6.29-rc8: pwc mmap always failes with EAGAIN
Submitter  : Markus <M4rkusXXL@web.de>
Date       : 2009-03-14 16:42
References : http://marc.info/?l=linux-kernel&m=123704902201378&w=4

This entry is being used for tracking a regression from 2.6.28.  Please don't
close it until the problem is fixed in the mainline.

Comment 1 Fryderyk Dziarmagowski 2009-03-25 09:32:00 UTC

I can confirm it. I got a Philips SPC 900NC USB webcam working with 2.6.28.x but it fails with 2.6.29 (causes popular propertiary video conferencig software to crash)
Same failure as Markus described:
(from gstreamer-properties)
Could not map buffers from device '/dev/video0'
Failed to create buffer pool: Resource temporarily unavailable]
dmesg doesn't provide any information, just standard pwc output:

pwc: Supports Philips PCA645/646, PCVC675/680/690, PCVC720[40]/730/740/750 & PCVC830/840.
pwc: Also supports the Askey VC010, various Logitech Quickcams, Samsung MPC-C10 and MPC-C30,
pwc: the Creative WebCam 5 & Pro Ex, SOTEC Afina Eye and Visionite VCS-UC300 and VCS-UM100.
pwc: Philips SPC 900NC USB webcam detected.
pwc: Registered as /dev/video0.
usbcore: registered new interface driver Philips webcam

my setup:
linux 2.6.29 SMP preempt mod_unload CORE2 4KSTACKS
I can provide more detailed info, just ask me.

Comment 2 Fryderyk Dziarmagowski 2009-03-27 17:09:18 UTC

applying patches:
http://marc.info/?l=linux-kernel&m=123691716419111&w=2
and
http://marc.info/?l=dri-devel&m=123606627824556&w=2

solves the problem.

Comment 3 Alex Villacis Lasso 2009-03-31 23:32:05 UTC

Looks like bug 12920 and this bug are duplicates of each other.

Comment 4 Suresh B Siddha 2009-04-04 00:24:45 UTC

Fix for this issue (http://marc.info/?l=linux-kernel&m=123854290308079&w=2) went into linux-2.6.29.1. Can we please check 2.6.29.1 and close this bug if the issue is resolved?