Linux on a Lenovo T550 Updated
As I posted recently, I have a new Lenovo T550 thinkpad which (for the moment) I have installed Debian 8 on. I recently compiled and installed the (latest) 4.1 kernel on it; on reboot everything worked fine - except wifi. Checking in the kernel log showed the cause:
[ 4.279314] iwlwifi 0000:03:00.0: request for firmware file 'iwlwifi-7265D-10.ucode' failed.
So it appears that the kernel driver in v4.1 requires a newer version of the firmware for this Intel wireless chip. I downloaded the iwlwifi package from the debian sid archive, then:
ar vx firmware-iwlwifi-*.deb xz -cd data.tar.xz | tar xf - sudo cp lib/firmware/iwlwifi-7265D-10.ucode /lib/firmware
When on Debian there are of course other ways to achieve the effect, but the above should work for non-debian OSes too.
I presume the package would actually simply install on top of debian-stable without any ill effects, but (a) didn’t want to risk it, and (b) installed the kernel with ‘make install’ rather than turning it into a debian package, so thought installing the firmware manually too might be more appropriate.
The new kernel also appears to have resolved a graphics problem on my system. I’m currently running the xserver-xorg-video-intel driver from Debian Sid to get support for the broadwell graphics in my laptop. Under the 3.16 kernel performance would deteriorate significantly after a while - as if falling back to software rendering or similar, although I couldn’t find any relevant messages in kernel or xserver logfiles. This hasn’t happened with the 4.1 kernel yet .. fingers crossed!