Bug 5061

Summary:	unable to remove socket power
Product:	Drivers	Reporter:	Sanjoy Mahajan (sanjoy)
Component:	PCMCIA	Assignee:	linux-pcmcia
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	akpm, linux
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.13-rc6	Subsystem:
Regression:	---	Bisected commit-id:
Bug Depends on:
Bug Blocks:	5062
Attachments:	[PATCH] pcmcia/yenta: avoid PCI write posting problems

Description Sanjoy Mahajan 2005-08-13 21:45:43 UTC

Distribution: Debian testing

Hardware Environment: TP 600X, CardBus bridge: Texas Instruments PCI1450, using
Intersil (prism54) wlan card

Software Environment: in-kernel pcmcia drivers

Problem Description: 'cardctl eject' produces 
  PCMCIA: socket e248602c: *** DANGER *** unable to remove socket power

Ejecting the card physically does not produce those messages.

I notice this problem only with a 'low-latency preemptible kernel' (how the
choice is described in the make menuconfig).  In particular, the diff between
the kernel config that does not show the problem and the kernel config that does:

+CONFIG_DEBUG_PREEMPT=y
+CONFIG_HAVE_DEC_LOCK=y
+CONFIG_LOCK_KERNEL=y
-CONFIG_PREEMPT_VOLUNTARY=y
+CONFIG_PREEMPT_BKL=y
+CONFIG_PREEMPT=y



Steps to reproduce:

Stick in my WLAN card (prism54 chipset), then 'cardctl eject'

Comment 1 Daniel Ritz 2005-08-17 14:11:45 UTC

Created attachment 5661 [details]
[PATCH] pcmcia/yenta: avoid PCI write posting problems

[PATCH] pcmcia/yenta: avoid PCI write posting problems

extend cb_writel(), exca_writeb(), exca_writel() to do a read[lb]() after
the write[lb]() to avoid possible problem with PCI write posting.

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>