Re: [9fans] No signal on some monitors with Raspberry Pi 400
i even get 4k@60hz here on a rpi4 on 9front, but there was a lot of
interference with bluetooth, wifi and usb3, it might be you need an
extra strong signal, did you try with a short cable that has a high
bandwidth?
On 3/10/21, Bakul Shah wrote:
> On Mar 10, 2021, at 8:53 AM, Richard Miller <9f...@hamnavoe.com> wrote:
>>> That is, if I plug into a ~10 year old Vizio television
>>> everything works fine at a reasonable resolution (1280x1024? I haven't
>>> yet figured
>>> out which utility to use to query display properties)
>>
>> Here's a simple way:
>>
>> term% echo `{dd -if /dev/screen -bs 64 -count 1}
>>
>>> , but if I plug it into a Dell
>>> S2817Q the monitor says "No signal detected."
>>
>> That's a 4k monitor, I think. The native resolution is probably too big
>> to fit in the virtual area allowed for the kernel frame buffer. (Lack of
>> foresight - monitors were smaller when 9pi was first done.)
>>
>> I'll see about fixing that soon. Meanwhile, you should be able to use
>> hdmi_group and hdmi_mode settings in config.txt to request a lower
>> resolution.
>> Or add something like "vgasize=1600x1200x16" to the command line in
>> cmdline.txt -
>> either method should work.
>
> Not sure how things are different in pi4+pi9 but I was able to get 4K@20Hz
> under plan9 back in 2014 on the original pi. Not sure I can find that
> SDcard now but the settings were based on what I gleaned from this thread:
> https://www.raspberrypi.org/forums/viewtopic.php?t=79330
--
9fans: 9fans
Permalink:
https://9fans.topicbox.com/groups/9fans/T295835c4cafb6d4f-M5444f7c46a5f07d392c4a08c
Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
Re: [9fans] No signal on some monitors with Raspberry Pi 400
On Mar 10, 2021, at 8:53 AM, Richard Miller <9f...@hamnavoe.com> wrote:
>> That is, if I plug into a ~10 year old Vizio television
>> everything works fine at a reasonable resolution (1280x1024? I haven't yet
>> figured
>> out which utility to use to query display properties)
>
> Here's a simple way:
>
> term% echo `{dd -if /dev/screen -bs 64 -count 1}
>
>> , but if I plug it into a Dell
>> S2817Q the monitor says "No signal detected."
>
> That's a 4k monitor, I think. The native resolution is probably too big
> to fit in the virtual area allowed for the kernel frame buffer. (Lack of
> foresight - monitors were smaller when 9pi was first done.)
>
> I'll see about fixing that soon. Meanwhile, you should be able to use
> hdmi_group and hdmi_mode settings in config.txt to request a lower resolution.
> Or add something like "vgasize=1600x1200x16" to the command line in
> cmdline.txt -
> either method should work.
Not sure how things are different in pi4+pi9 but I was able to get 4K@20Hz
under plan9 back in 2014 on the original pi. Not sure I can find that
SDcard now but the settings were based on what I gleaned from this thread:
https://www.raspberrypi.org/forums/viewtopic.php?t=79330
--
9fans: 9fans
Permalink:
https://9fans.topicbox.com/groups/9fans/T295835c4cafb6d4f-M855b50cfb52355dd9a906ae2
Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
Re: [9fans] No signal on some monitors with Raspberry Pi 400
> That is, if I plug into a ~10 year old Vizio television
> everything works fine at a reasonable resolution (1280x1024? I haven't yet
> figured
> out which utility to use to query display properties)
Here's a simple way:
term% echo `{dd -if /dev/screen -bs 64 -count 1}
> , but if I plug it into a Dell
> S2817Q the monitor says "No signal detected."
That's a 4k monitor, I think. The native resolution is probably too big
to fit in the virtual area allowed for the kernel frame buffer. (Lack of
foresight - monitors were smaller when 9pi was first done.)
I'll see about fixing that soon. Meanwhile, you should be able to use
hdmi_group and hdmi_mode settings in config.txt to request a lower resolution.
Or add something like "vgasize=1600x1200x16" to the command line in cmdline.txt
-
either method should work.
--
9fans: 9fans
Permalink:
https://9fans.topicbox.com/groups/9fans/T295835c4cafb6d4f-Md4f814e7c44f86d9f584b403
Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
