No Sound on Raspberry Pi

Resolution as given by the monitor. I’m afraid I wouldn’t know how to ascertain what resolution’s output from RISC OS or the GPU.

It would seem that the hdmi/vga converter possibly plays a part in all this, one that I don’t understand, but I’m hoping there’s something I can configure to force the resolution I want yet still keep audio.

To find out what RISC OS is outputting just click on the screen icon on the right of the icon bar.
What the GPU is outputing will be defined by the config.txt file and/or the GPU’s reading of the EDID but it should be what the monitor says its getting!

Clicking on the display icon after a cold boot says it’s 1280×960 (it’s telling fibs!) and after a reboot it says exactly the same (which this time looks to be true).

I don’t know whether it’s significant but after a cold boot the start-up display occupies the whole screen and the aspect ratio looks proportional, though the aspect ratio of the screen it then boots into looks decidedly distorted. After a reboot the starter screen is more letterbox in aspect, although it still looks OK, and the screen it boots into looks absolutely fine.

I might be barking up the wrong tree but it’s almost as though with a cold boot something is defining the resolution before the OS itself is fully booted in, but with a warm boot the OS skips the initial bootstrapping sequence and is then able to respond to the RISC OS monitor configuration (??).

Clicking on the display icon after a cold boot says it’s 1280×960 (it’s telling fibs!) and after a reboot it says exactly the same (which this time looks to be true).

After a cold boot 1280×960 is therefore what RISC OS is presenting to the GPU (it doesn’t lie) but the GPU is transforming that into what it thinks [from config and EDID] that the monitor requires.

After a warm boot RISC OS is still 1280×960 but the GPU now thinks that the monitor requires something different (and correct?).

The problem is therefore not with RISC OS at all. Possibly the GPU is failing to read the EDID signal from the monitor properly. Using a HDMI to VGA convertor is almost certainly the reason for your problems. If you include a proper monitor mode specification in the config.txt file – which is essential if the monitor EDID is not available but is not included in the standard SD card image for RISCOS as it assumes an HDMI connected monitor – then you should solve this.

Possibly the GPU is failing to read the EDID signal from the monitor properly.

Isn’t there a config option hdmi_mode or somesuch to force a specific mode?

After a cold boot 1280×960 is therefore what RISC OS is presenting to the GPU (it doesn’t lie) but the GPU is transforming that into what it thinks [from config and EDID] that the monitor requires.

IIRC one of the config.txt options tells the Pi to ignore the EDID data…

… right quick dig and the brain cells do seem to be functioning for recall:

http://elinux.org/RPi_config.txt
Under video options:

hdmi_safe Use “safe mode” settings to try to boot with maximum hdmi compatibility.
This is the same as the combination of: hdmi_force_hotplug=1, config_hdmi_boost=4, hdmi_group=2, hdmi_mode=4, disable_overscan=0
hdmi_safe=1

hdmi_ignore_edid Enables the ignoring of EDID/display data if your display is a crappy Chinese one

hdmi_edid_file when set to 1, will read the edid data from the edid.dat file instead of from the monitor.¹

hdmi_edid_file=1

hdmi_force_edid_audio Pretends all audio formats are supported by display, allowing passthrough of DTS/AC3 even when not reported as supported.

avoid_edid_fuzzy_match Avoid fuzzy matching of modes described in edid. Picks the standard mode with matching resolution and closest framerate even if blanking is wrong.

hdmi_ignore_cec_init Doesn’t sent initial active source message. Avoids bringing (CEC enabled) TV out of standby and channel switch when rebooting.

Hi folks,
Just wanted to say “Hi” as a new user to RISC-OS, what a revalation! I have to admit I was tearing my hair out over the “no sound” issue with the Raspi RISC-OS release.

Following threads from various forums I had made changes to my config.txt file to no avail. That is until I read the posts on this forum and tried the “hdmi_force_edid_audio=1” option. This has finally cured my missing sound issue and I now have sound over the HDMI cable to the HDTV. Previous attempts with “hdmi_safe=1” and “hdmi_drive=2” had failed to produce any audio output.

The only thing I am still unclear on is why the Raspian Wheezy distribution auto detects the HDTV and routes the sound automatically via the HDMI cable with no modification to the config.txt file required.

Anyway, everything seems fine now and I look forward to learning to use RISC-OS and re -learning BBC BASIC.

Regards to all,

pipuppy

The only thing I am still unclear on is why the Raspian Wheezy distribution auto detects the HDTV and routes the sound automatically via the HDMI cable with no modification to the config.txt file required

Is the firmware the same version? (start.elf)

Hi again,

Jess Hampshire wrote:
“Is the firmware the same version? (start.elf)”

I am not sure, its the version bundled with the RISC-OS image available on the http://www.raspberrypi.org/downloads page.

Is it indeed possible to change/update start.elf without messing-up the RISC-OS image?

Regards,
pipuppy

Firstly, thanks to all who responded to my requests for help with my problems with sound and then later with the incorrect monitor aspect. I’ve learnt an awful lot through your comments, which I guess is pretty much in keeping with the philosophy behind the Raspberry Pi!

I had to put the Pi to one side for several weeks while I dealt with more pressing matters but now I’m back I’ve solved my monitor aspect problem quite by chance and report it back here in case it’s of any help to anyone else.

To go back to the very beginning, when I booted up the Pi for the very first time I got no picture on the monitor, just a message to say the signal wasn’t understood or some such. I found by trial and error that if I switched on in the sequence: HDMI converter – monitor – Raspberry Pi – then it would work OK but I was left with a monitor aspect which was out of plonk from a cold boot and needed a warm boot to get it right. I altered the Config file as in my comment of 29/1/13 but it didn’t cure the problem at that point.

I’ve just discovered, again quite by chance, that if I switch on in the reverse sequence (ie RPi – monitor – HDMI converter) it boots into the correct aspect from a cold boot. This only works after I’ve altered the Config file (which I discovered after upgrading to RC8). I feel it’s almost certainly something to do with the way my ‘HDMI/VGA 1080 Ultimate’ video converter works but may be applicable to other HDMI to VGA converters for all I know. The above solution works with both RC6 and RC8 by the way (didn’t try RC7). [EDIT: see my later post below!]

Hope this may be of help if someone encounters similar problems. Thanks again to all who offered suggestions & advice – it was a steep learning curve for me but all good stuff!

It is implied but can you confirm sound is also now working?
Is sound connected to the Pi’s 3.5mm Audio out socket or does the HDMI-VGA also split out Audio?
What setting do you have in config.txt? (posting the whole file may be best!)
Chris

Sound is now working, from the HDMI/VGA converter for RISC OS (funnily enough this doesn’t work for Linux, the audio cable has to go in the Pi’s own 3.5mm Audio Out socket, won’t work in the converter’s audio socket).

Just firing up the Pi to look at the config.txt file; bl**dy hell! – despite trying the above ‘solution’ numerous times yesterday, it now only boots into the correct aspect if the converter is switched on first . I don’t understand it. Hang on a mo’ while I bang my head repeatedly on the desk…

Ah, that’s better. I guess the point is that if someone doesn’t get the right (or no) picture using a HDMI/VGA converter, it might be worth exploring the sequence in which devices are turned on, to see if that makes any difference.

As to my config.txt file, it reads:

fake_vsync_isr=1
gpu_mem=64
init_emmc_clock=100000000
kernel=RISCOS.IMG

hdmi_group=2
hdmi_mode=32
hdmi_drive=2
disable_overscan=1

Good Evening Everyone,

As a newcomer to Riscos 5.28 I am running into an issue with picture/sound on my Pi 4. I’ve followed the advice here and have managed to get the correct picture ratio and sound on my HDMI 1 port. However, when I try to run any full-screen game (such as Mad Professor Moriarty), I get sound but the screen remains blank/black.

If I switch to HDMI 2, then I get the image, but no sound. I’ve tried splitting the output by using the sound on HDM1 and picture on HDMI 2, but, plugging anything into HDMI 1 disables HDMI 2 and all I get is the “rainbow” screen normally seen if you boot a Pi with no OS.

I know it’s not the software because it runs fine on my A3000 with Riscos 3.11. It has been driving me insane trying to figure this out, and it only happens with games that run full screen/boot emulation.

Any help will be so appreciated!

Have you tried juggling with the main menu
Preferences > Screen Configuration > Layout > Screens
to make both active?

Good Morning, and thank you for the response. When I click on the Screen icon in configuration, I get this error message:

‘Resources:$.Resources.ScreenMode.Monitors.EDID0’ not found.

Could this be the root of the problem? I have added the following lines to the config file:

hdmi_group=2
hdmi_mode=32
hdmi_drive=1
disable_overscan=1
hdmi_ignore_edid_audio=1

These fixed most of my display/sound issues but could they be causing the error message?

Whoops – so sorry. My advice was for use with Raspberry Pi OS, not RISC OS. Try

hdmi_group=1 (Use CEA mode)
hdmi_drive=2 (Use HDMI if available)

in $.!Boot.Loader.CONFIG/TXT

when I try to run any full-screen game (such as Mad Professor Moriarty), I get sound but the screen remains blank/black.

Put disable_mode_changes in CMDLINE/TXT (you may need to create this file; it lives alongside CONFIG/TXT).

I get sound but the screen remains blank/black

Assuming you’re using ADFFS, refer to the Pi requirements section on the download page for the version you’re using. That details to various config settings needed for it to work correctly.

If there’s additional steps required specifically for the Pi4, please let me know so I can update the page.