Tuesday, July 30, 2013

Gentoo, Linux 3.10 and Nvidia drivers (also Linux 3.11)

Update: Check the end for Linux 3.11

Looks like binary Nvidia drivers aren't compatible with Linux kernel 3.10 for some reason. There's a patch (found it in Nvidia forum DevZone) but for some reason Gentoo maintainers won't include it in gentoo-sources even as an use flag. Portage only tells me:

* Gentoo supports kernels which are supported by NVIDIA
* which are limited to the following kernels:
* <sys-kernel/gentoo-sources-3.10
* <sys-kernel/vanilla-sources-3.10

* You are free to utilize epatch_user to provide whatever
* support you feel is appropriate, but will not receive
* support as a result of those changes.

* Do not file a bug report about this.

I haven't heard about epatch_user before but it seems perfeclty reasonable for Gentoo to have something like this. Basically it is a way for user to easily patch sources to be built without editing ebuilds.

I started to look for info about how to use this epatch_user. Gentoo handbook was the first place to look but I didn't get it to work with that info. After looking at other pages I found out what was wrong. I think the handbook should say
instead of
where <name> is an arbitrary name for the patch. Anyways I wrote a (very) short howto for those with the same problem.

A short howto

Run all the commands as root:
mkdir -p /etc/portage/patches/x11-drivers/nvidia-drivers
wget http://pastie.org/pastes/8123499/download -O /etc/portage/patches/x11-drivers/nvidia-drivers/nvidia-drivers-325.08-lnx311-rc0.patch
emerge nvidia-drivers

Quite easy. Of course this assumes you have gentoo-sources-3.10.x configured and compiled and nvidia-drivers-325.08 unmasked.

Linux 3.11

Seems like something different for Linux 3.11. That's solved by a patch from https://bugs.gentoo.org/show_bug.cgi?id=482168. Put that file in /etc/portage/patches/x11-drivers/nvidia-drivers-325.15/ and Nvidia 325.15 should compile for Linux 3.11.

Monday, July 8, 2013

Regim and processing astrophotos in Linux only

Thanks to Astrophotography community in G+ I found Regim. I've stacked my astrophotos using Deepskystacker in Windows and everything else (with computer in general) I do in Linux, so booting to Windows is always a pain. Now it seems that's over. Regim is written on Java and it works quite well in Linux. I've experienced couple of crashes but otherwise everything seems good.

Regim is easy to use, extremely automatic and does easily some things I haven't found in DSS. For example removing gradient which is quite handy for me since I take photos on my backyard. Every one of them has some gradient from nearby city lights.

On the other hand Regim is quite limited in what it does and it really requires real image processing software to get anything done.

I tried Regim on some of my old imaging data and compared it to what I got with DSS. Here's PanSTARRS comet close to Andromeda processed with DSS.

PanSTARRS and Andromeda stacked with DeepSkyStacker

Here's what I got with Regim. After stacking I removed the gradient, adjusted white balance with Regims "manual" tool (I set the b-v value of Andromeda center to 0.63), and did the final adjustments in Darktable. So everything in Linux only. Finally.

PanSTARRS and Andromeda stacked with Regim

Now if only Gimp could handle 16bit colours...