Comments

Post a Comment

Popular posts from this blog

gnome 3.6 and keyboard layout configuration

Gnome 3 devs are stupid enough to remove features before some replacement is implemented. Simplified nautilus and (what's much more important for me!) broken keyboard layout configuration. Well, you still can configure what layouts to use, but you can't choose usual shortcut to switch layout, and you can't configure led to indicate alternative layout. Well, I still can use setxkbmap (setxkbmap -layout "us,ru" -option "grp:caps_toggle,grp_led:scroll"), but that's f***ing ridiculous to remove things that were working here for years and propose nothing for replacement! They broke core functionality (who can work without a keyboard?!), and it makes me sick! Update:  more haterays to gnome-devs! Gnome 3 overrides xkbmap settings somewhere, I wonder if there's a way to prevent it... Update-2:  you can remove gnome-settings-daemon keyboard plugin as a workaround (sudo rm /usr/lib/gnome-settings-daemon-3.0/libkeyboard.so)
Read more

OLED brightness in Linux

Recently I've got a new laptop with OLED panel only to find out that brightness control for OLED panels is not yet supported in Linux. Archlinux wiki page mentions using gamma ramp for controlling perceived brightness using hackish userspace tools (icc-brightness), so my first thought was to implement a hack for i915 driver to expose backlight interface that actually adjusts gamma ramp. So I went to #dri-devel to ask around whether this idea sounds too crazy and it turned out that there are better ways than using gamma ramp. Basically if you use gamma ramp you essentially reduce dynamic range, i.e. if you have 8 bits per pixel at 50% brightness you would get 7 bit, at 25% - 6 bit and that will result in banding artefacts at low brightness levels. To overcome that issue OLED panels actually have an interface to control brightness. There are at least 2 competing "standards" - VESA and Intel proprietary. First one is already supported by i915 driver while latter is not. Unfo
Read more

Hacking u-boot for Pinebook. Part #1 - using FEL

It's been a while since I posted to my blog. A lot of things happened since then, I guess the most important is -- I moved to Canada. I've been living in Vancouver (OK, Greater Vancouver) with my wife and cat for more than 2 years now. But enough about me, let's get back to the topic. Recently I've got a Pinebook , mostly for hacking purposes. It's pretty nice device - quad-core Allwinner A64 CPU, 2GB LPDDR3 RAM, eMMC storage, etc, etc. See pine64.org for full specs. But unfortunately it comes with BSP kernel from Allwinner which is pretty ancient - 3.10 (released in 2013, more than 4 years ago!) Hopefully, mainline support for A64 is in pretty decent shape, see  http://linux-sunxi.org/Linux_mainlining_effort . Sure some things are missing - LCD, sound, power management, and that's not all. But it's good - there's something to hack on, right? So I decided to start with u-boot. Hopefully, Allwinner SoCs support boot over USB - it's called FEL,
Read more