From mboxrd@z Thu Jan 1 00:00:00 1970 From: Larry Finger Date: Tue, 20 Apr 2010 12:07:40 -0500 Subject: System freezes with 2.6.33 In-Reply-To: <20100420162751.25907.qmail@stuge.se> References: <20100418071932.GB15229@happy.exit> <4BCB3071.8030500@lwfinger.net> <20100420143358.GA1990@happy.exit> <20100420155140.14443.qmail@stuge.se> <20100420180704.74972858@Mobile-Workstation.localdomain> <20100420162751.25907.qmail@stuge.se> Message-ID: <4BCDDF5C.2040901@lwfinger.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: b43-dev@lists.infradead.org On 04/20/2010 11:27 AM, Peter Stuge wrote: > Daniel Kuehn wrote: >>>> I have also tried disabling the radio using the switch, and then >>>> there is no freeze. When I enable the radio back, it freezes again. >>> >>> Could b43 experts please outline what happens w.r.t. the PCIe bus >>> when radio is disabled using the switch as described above? >> >> Doesnt the switch "just" turn it off hardware wise? No, the hardware is still powered. I think the signal from the switch disables the radio, but I'm not sure of that. > I doubt that. PCIe can do hotplug but it's only used in high-end > systems, not a mini-note. > > >> As in that the OS doesnt even know it exists then because more or >> less the power is cut to it. > > Usually the switch generates an electrical signal which goes through > the system board over to the wifi card, and there it will have > control over the RF part, and yes disable radio communication, but > no, not the entire wifi card. As I have understood the b43 hardware > can also read this electrical signal and report it's status to the > driver, but it is impossible to override the hardwired "kill" switch > from the driver. > > This is why I ask for advice from the b43 experts, since maybe my > description above is too simplistic, and the kill signal will > actually cause more things to happen on the wifi card. > > Anything related to the host bus is of particular interest. See below. > What happens in the firmware w.r.t. the kill switch? I do not think the firmware knows anything about it other than possible interaction with the driver through the contents of shared memory. > What does openfwwf do? Do you mean with respect to the freeze? The openfwwf is only for Revision 5 802.11 cores - this one is Rev 13. There are a number of code paths that are not used when the radio switch is off. For instance, the device will not do DMA, which might be a clue. Yuval: If you are willing to generate your own kernel, please set 'CONFIG_B43_FORCE_PIO=y' in your configuration. That will skip DMA completely. Larry