* [9fans] Seiki 4k + RPi + Plan9
@ 2014-07-07 17:05 Bakul Shah
2014-07-07 23:22 ` kokamoto
0 siblings, 1 reply; 5+ messages in thread
From: Bakul Shah @ 2014-07-07 17:05 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
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.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] Seiki 4k + RPi + Plan9
2014-07-07 17:05 [9fans] Seiki 4k + RPi + Plan9 Bakul Shah
@ 2014-07-07 23:22 ` kokamoto
2014-07-07 23:53 ` Bakul Shah
2014-07-08 0:44 ` kokamoto
0 siblings, 2 replies; 5+ messages in thread
From: kokamoto @ 2014-07-07 23:22 UTC (permalink / raw)
To: 9fans
Would you please to explain more about the meaning of:
> hdmi_group=2
> hdmi_mode=87
> config_hdmi_boot=4
Kenji
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] Seiki 4k + RPi + Plan9
2014-07-07 23:22 ` kokamoto
@ 2014-07-07 23:53 ` Bakul Shah
2014-07-08 0:44 ` kokamoto
1 sibling, 0 replies; 5+ messages in thread
From: Bakul Shah @ 2014-07-07 23:53 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
On Tue, 08 Jul 2014 08:22:29 +0900 kokamoto@hera.eonet.ne.jp wrote:
> Would you please to explain more about the meaning of:
>
> > hdmi_group=2
> > hdmi_mode=87
These magic numbers were gleaned from
http://www.raspberrypi.org/forums/viewtopic.php?f=38&t=79330
config.txt is documented at
http://elinux.org/RPi_config.txt
Not sure how complete it is as they add more stuff for new
firmware capabilities etc. hdmi_mode=87 is brand new and not
yet in the above document. Somre more details at
http://www.raspberrypi.org/forums/viewtopic.php?t=5851
There are two commands under Raspbian, tvservice and
edidparser. Together they can be used to dump out what a
display returns in terms of the modes it supports etc.
> > config_hdmi_boot=4
Sorry, this should be
config_hdmi_boost=4
It boosts the HDMI signal strength. Normal signal strength
may not be enough if the hdmi cable is long.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] Seiki 4k + RPi + Plan9
2014-07-07 23:22 ` kokamoto
2014-07-07 23:53 ` Bakul Shah
@ 2014-07-08 0:44 ` kokamoto
2014-07-08 0:55 ` erik quanstrom
1 sibling, 1 reply; 5+ messages in thread
From: kokamoto @ 2014-07-08 0:44 UTC (permalink / raw)
To: 9fans
Thanks.
Now I got 1376x768 on my screen.
Sharp's manual says it can also use 1920x1080, which
may be too small character to my old eyes.☺
I edited /n/9fat/CONFIG.TXT as
framebuffer_width=1376 etc.
Kenji
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [9fans] Seiki 4k + RPi + Plan9
2014-07-08 0:44 ` kokamoto
@ 2014-07-08 0:55 ` erik quanstrom
0 siblings, 0 replies; 5+ messages in thread
From: erik quanstrom @ 2014-07-08 0:55 UTC (permalink / raw)
To: 9fans
> Sharp's manual says it can also use 1920x1080, which
> may be too small character to my old eyes.☺
why not just use a bigger font?
- erik
^ permalink raw reply [flat|nested] 5+ messages in thread
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2014-07-07 17:05 [9fans] Seiki 4k + RPi + Plan9 Bakul Shah
2014-07-07 23:22 ` kokamoto
2014-07-07 23:53 ` Bakul Shah
2014-07-08 0:44 ` kokamoto
2014-07-08 0:55 ` erik quanstrom
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