From mboxrd@z Thu Jan 1 00:00:00 1970 To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Date: Mon, 7 Jul 2014 10:05:51 -0700 From: Bakul Shah Message-Id: <20140707170551.F16C3B82A@mail.bitblocks.com> Subject: [9fans] Seiki 4k + RPi + Plan9 Topicbox-Message-UUID: 011e851a-ead9-11e9-9d60-3106f5b1d025 Given that the Seiki 39" 4k (3840x2160) display prices have come down quite a bit (now $329 @ amazon) I wanted to see if I can use it with the RPi & plan9 as well. 1. You will need one plan9 fix: % diffy /sys/src/9/bcm/mmu.c 307c307 < cachedwbse(pte0, pte - pte0); --- > cachedwbse(pte0, (pte - pte0)*sizeof(PTE)); 2. You will need to upgrade firmware to at least June 18 version (/sources seems down at the moment but the image Richard put up at /n/sources/contrib/miller/9pi.img.gz has it). Or follow instructions from the RPi website. 3. You will need to fiddle with config.txt. gpu_mem=64 framebuffer_width=3840 framebuffer_height=2160 hdmi_group=2 hdmi_mode=87 hdmi_cvt 3840 2160 15 max_framebuffer_width=3840 max_framebuffer_height=2160 hdmi_pixel_freq_limit=400000000 disable_overscan=1 I also needed config_hdmi_boot=4 to boost the hdmi signal. You may not. That is it! Some caveats: Its screen feels huge! I sit about 30" from it. It may be too big for a small or shallow office. It may be hard on your eyes or neck or back. I still haven't found the right height for it and may end up installing it on a wall. I have used it for a couple of weeks with a MBP but hardly at all as a plan9 terminal. I can run it at 30Hz at 4k resolution with a recent MBP but this resolution does not work with a late 2011 MBP. At 30hz some people find its cursor to be laggy. Didn't bother me. As per a RPi forum thread this pixel clock should work upto 24Hz. For 24Hz change the hdmi_cvt line to hdmi_cvt 3840 2160 24 The setting I used is for 15Hz and the cursor is a bit laggy. You will probably need to install new firmware on the Seiki and change some of its default settings.