The iwlwifi driver in gentoo-sources-3.4.0 incorrectly sets the max TX power limit to 0dBm (for reference the limit was 15dBm in gentoo-sources-3.3.5). The below email transcript is a condensed summary of the issue: >>> What I am seeing is a difference in TX-power (as reported by >>> iwconfig) which affects my connectivity to my AP. >> Interesting. Can you show/compare the output of "iw list" (not "iwlist") on > both kernels? > > Certainly, see the attached files. Thanks. As you can see all the channels are listed with 0 dBm max TX power, this is due to a bug I just found recently. Please try this patch, it's on the way to upstream and 3.4.x stable: http://thread.gmane.org/gmane.linux.kernel.wireless.general/91661 johannes Reproducible: Always Steps to Reproduce: Build gentoo-sources 3.4.0 Observe 'iw list' output for Intel Centrino Wireless 6300 card Actual Results: output will list max tx power as 0dBm Expected Results: output should list max tx power as >0dBm (15dBm according to 3.3.5 kernel) I am working on patching the 3.4.0 sources with the changes Johannes pointed out. However, my latest attempt caused the kernel to crash at boot. If I get a working patch, I will post it here.
Created attachment 313953 [details, diff] Patch based on inlined email transcript This is the patch I created based on the email transcript I inlined in the bug report. I just started using it, but so far it looks good.
Can you test a kernel >= 3.4.4. (vanilla or gentoo-sources). The referenced patch is in both kernels. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=a5fdde28b4f5fb756032e7ad2c6fcdcffde20958
(In reply to comment #2) > Can you test a kernel >= 3.4.4. (vanilla or gentoo-sources). > > The referenced patch is in both kernels. > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git; > a=commitdiff_plain;h=a5fdde28b4f5fb756032e7ad2c6fcdcffde20958 Patch was committed in 3.4.4. Based on previous conversations with upstream and wifi behavior, the issue looks like it is fixed in that version.
Patch released in current kernels.
