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Sound fix for 5.4 kernel on Apollo Lake

December 10, 2019 — BarryK

I have posted about sound being broken on my Acer Aspire 1 laptop, model A114-31-C014. Booting EasyOS with the 5.4.1 or 5.4.2, the kernel reports no sound devices:

There was a fix reported on an Arch Linux forum, however that was a different problem:

Many days have been spent trying to fix this, but I got up this morning determined to give it another go. I examined the kernel modules loaded by the 5.2.21 kernel, compared with the 5.4.2 kernel, and began a process of elimination.

I found a module that is loading and breaking sound, 'snd_soc_skl':

# lspci -nnk
00:0e.0 Audio device [0403]: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Audio Cluster [8086:5a98] (rev 0b)
Subsystem: Acer Incorporated [ALI] Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Audio Cluster [1025:1195]
Kernel driver in use: snd_soc_skl
Kernel modules: snd_soc_skl, snd_hda_intel

'snd_soc_skl' is for the Sky Lake CPU, it should not be loading for my Apollo Lake N3450 CPU.

After removing that module, running 'depmod' and rebooting:

00:0e.0 Audio device [0403]: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Audio Cluster [8086:5a98] (rev 0b)
Subsystem: Acer Incorporated [ALI] Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Audio Cluster [1025:1195]
Kernel driver in use: snd_hda_intel
Kernel modules: snd_hda_intel

...and sound works. Now I need to find where to report this... 

Tags: easy

Easy Pyro versions 1.2.9 and released

December 09, 2019 — BarryK

EasyOS Pyro is the "old" series, superseded by the Buster series, however Pyro is still receiving updates that match those of Buster releases. The latest Easy Buster is 2.1.9 and, announced earlier today:

Easy Pyro is built with packages compiled from source in 'oe-qky-src', my port of OpenEmbedded, and the first releases were for Quirky Linux, mid-2017. Since then, there have been some package upgrades, such as for Qt5 and Xorg, later in 2018 and early 2019, however the core packages are mostly 2017 vintage.

Although many of the packages are getting a bit "long in the tooth", the Pyro series still works great. Although the Buster series is intended to be the replacement, many users like Pyro, me included, so it is still getting updates.

Please read the above link for the Buster announcement, as the features also apply to Pyro. Except, of course, Pyro is not built with DEBs.

Here is the primary download site:

Mirrored here:

As for Buster, there are two versions, 1.2.9 has the 5.2.21 kernel, has the 5.4.1 kernel.

Release notes:

Feedback is welcome here: 

Tags: easy

Easy Buster 2.1.9 and released

December 09, 2019 — BarryK
Another release of EasyOS Buster series, versions 2.1.9 and The reason for the two version numbers, is the 2.1.9 build is with the 5.2.21 kernel, and is with the 5.4.2 kernel.

And the reason for building with two different kernels, is that audio does not work on some hardware with the 5.4.x kernel (so far, 5.4, 5.4.1 and 5.4.2).

Here is the primary download site, courtesy of

...the German and French builds are 2.1.9 only, as is the ISO file. I have only uploaded the English build of

Thanks to NLUUG, the files are mirrored here:

The reason that I am keen to use the 5.4.x kernel is due to the new "lockdown" feature. This is used in the "Copy session to RAM & disabled drives" kernel boot option, which takes security to a new high. This boot option runs Easy entirely in RAM, with no access to the drives, except for ones that you plugin after bootup. Kernel lockdown decreases the risk, however small, of someone figuring out some very clever way to make PC drives accessable.

Try, if audio does not work you will have to fall back to 2.1.9.

There are release notes here:

If you need help with writing the downloaded file to a USB-stick, or anything else with installing and booting, read this:

The next release of Easy Pyro, the older series of EasyOS, but still being updated, is expected to be uploaded in a couple of days.

Feedback is welcome: 

Tags: easy

Audio fix for 5.4.x kernel

December 08, 2019 — BarryK

Oh joy, a fix! Feodor sent me an email, with these links:

The last 4-5 days have been frustrating. I tried various processes of elimination, trying to fix sound. Finally, gave up and compiled older kernels for the next releases of Easy Buster and Easy Pyro.

Blog post a few days ago:

Logged into gmail this morning, and there was the email from Feodor.

Looks like we are back in business with 5.4.x. OK, I will now compile the 5.4.2 kernel, for Buster and for Pyro, with SND_HDA_INTEL_DETECT_DMIC disabled. 

Oh... bother. I found that this is already disabled:

# HD-Audio
# CONFIG_SND_HDA_CODEC_CA0132_DSP is not set
# end of HD-Audio

So, that was a fix for others, but not for my laptop. 

Tags: easy

Radical rethink of the basin-type distiller

December 05, 2019 — BarryK

I posted this morning some reflections on how the simple-basin prototype #2 achieved a high efficiency, with thoughts to enhance even further:

I have now got an idea how the frame can be collapsible, completely flat, for easy transportation. That is one new thought, that will be explained in a later blog post.

Another rethink is how to achieve a flat black floor for the basin. So far, have been spreading black silicone sealant, two 300gm tubes required for a 0.35 - 0.4 metre-cubed floor.

There are various problems with spreading silicone sealant. One is to find all pin-head holes. Another is to get the surface smooth. Then there is the messiness of the application.

A solution is a glass floor for the basin, with a thin black silicone sheet stuck on it. This would give perfect flatness, that will not warp, and suitable for very high temperatures.

The problem is to find a supplier of a large enough black silicone sheet. The exact dimensions yet to be determined, but somewhere around 700x550mm, 1mm thick. Last night I made some online enquiries to Australian suppliers, today only received one reply.

Reglin Rubber, based in Victoria, sent me a quote for a roll, 1200mm width, 10m long, sheet thickness 1mm. The quote is AU$148 including GST, and AU$40 postage. That would be enough for 28 distillers.

The biggest that I could find on eBay is 500x500mm, ditto Amazon. However, on Aliexpress I found this: 


...1m by 1m, 1mm thick, black silicone, AU$18.76 plus GST, and AU$27.05 for EMS ePacket postage (13 - 20 days delivery to my home, from China). Grand total AU$50.39. Rather a lot of money for a piece of silicone sheet, but want it, so ordered it.

EDIT 2019-12-09:
Yikes! I have received another reply. From Complete Rubber, based in Victoria:

Thinnest Black Silicone we can offer is 1.5mm Thick
1000 x 1200mm piece costs $499.00 + GST + Freight
We can supply 0.5mm, or 1.0mm Thick in RED or Translucent colour if acceptable
0.5mm - 1000 x 1200mm  Piece @ $441.00 + GST + Freight
1.0mm - 1000 x 1200mm Piece @ $385.00 + GST + Freight (Yes cheaper as is more common size purchased in the Market Place)

...a bit of a jump from $18.76 direct from China, and $148 for 10 metres from Reglin Rubber. 

Tags: nomad

Kernel 5.4.1 audio broken on Aspire1 laptop

December 05, 2019 — BarryK

So frustrating! Booting easy Pyro with 5.4.1 kernel on my Aspire1 laptop, the kernel reports that there are no audio devices. Different sound configuration, different firmware?, can't find any cause. The kernel just cannot find the audio device, even though it is a Intel audio chip. The laptop has the Apollo Lake series CPU.

There is another problem on that laptop. The mouse is a wired-USB type, plugged into a USB2 socket, and every now and again the mouse freezes, fixed by replugging the mouse.

The thing is, this mouse-freezing problem was not there before, with older kernels. Easy Pyro used to have 4.14.x kernels, then upgraded to 5.1.x, 5.2.x -- don't know when the freezing problem came in.

I am going to try an experiment. Have compiled the latest in the 4.14.x series, 4.14.157, and will try that.

I am now running Easy Pyro with 4.14.157 kernel, and audio works. However, the mouse still freezes. I get about half an hour of usage before the freeze. using it now, about another half hour, it hasn't frozen again.

In earlier tests, with later kernels (5.2.21 and 5.4.1) in most cases it is OK after the first freeze, but sometimes got the freezing happening more than once.

So it looks like a backport that has been applied to one of the 4.14.x series is the cause, but I am not going to try and find out which one. I have been down that road before, it is a very time-consuming process, to try and narrow it down to the commit that caused the problem. 

Tags: easy

Reflections on the basin-type proto-2 test

December 04, 2019 — BarryK

Yesterday was hot, ambient peaked at 41 degrees C (105.8 Fahrenheit), mostly clear blue sky, light breeze, mid-summer here in Perth Australia (Latitude 31 degrees), so the conditions were right to obtain maximum distilled water output that my basin-type prototype #2 is capable of. Here is the report of the test:

The panel produced 1.85 litres (0.49 gallons), with an effective glass area of 0.35 metre-squared, which calculates at about absolute efficiency of 48%, extraordinarily high for a simple basin-type distiller.

This blog post reflects on how that high efficiency was achieved.

There are three main factors:

  1. White painted inside walls
  2. Glass close to water surface
  3. Very low water depth

1. White painted inside walls
I posted about a research paper that obtained a 6.8% absolute efficiency gain by doing this:

In my case, I used white silicone sealant, Prosil 10.

2. Glass close to water surface
There are several research papers that have found the closer the glass to the water surface, the higher the efficiency. To achieve this, many designs have gone for a stepped basin-type still.

In my case, it is a compromise. The glass is about 15mm above the water at the front end, and about 115mm away at the back side. The distance of the glass at the back side is kept low by a very low glass angle of 10 degrees.

The downside of the 10 degrees is that for the latitude of Perth, 31 degrees, the efficiency of the distiller is going to drop right off in winter. The acute angle of the sun to the glass is going to mean most light will be reflected off the surface of the glass, instead of going into the distiller. I was thinking of using an external reflector in the winter.

3. Very low water depth
I only put 5 litres of water into the distiller, giving a water depth of 14mm average. However, my prototype #2 has a very uneven basin floor, due to misadventure experimenting with expanding foam, so the depth was variable, but there was water covering the entire surface.

There is one research paper that experimented taking the water depth down to 5mm and efficiency kept increasing as depth was reduced. This paper tested depths of 5, 10 and 20mm:

...they achieved output of 1141, 758, 305 millilitres in a day, from 5, 10 and 20mm water depth respectively. Quite an extraordinary variation.

So, if I had got the basin floor more flat, and setup the still to be very level, I could have put in less water and achieved higher efficiency.

Raising the efficiency further

Apart from lowering the water depth, is there anything else that can be done to further increase the efficiency of the simple basin-type distiller? Yes, there is...

I used 4mm thick window glass. Here are two more factors to increase efficiency:

  1. Thinner glass
  2. Low-iron glass

I have a collection of glass panes, that were cut for me by Casey at Perthglass, used in the various prototypes, and I just happened to have that 4mm piece available so used it. However, there is a research paper that has determined the efficiency improves as glass thickness is decreased.

This overview paper references another paper that shows efficiency improvement going from 4mm down to 3mm glass:

...that "other paper" is not free to download. Unfortunately, most academic research papers are seen as a business opportunity by companies such as Elsevier.

It was found that efficiency improved by 16.5% going from 6mm to 3mm thick glass.

I did locate another free-to-download paper that investigated glass thickness, can't locate it now.

Point-5 is low-iron glass. I have used ordinary window glass, that has some iron in it. This reduces the efficiency. However, low-iron glass is expensive. This paper reports that low-iron glass gave an increase of 6% efficiency compared with normal window glass:

I don't think that I will bother with obtaining that extra 6%. Will stay with normal cheap window glass, but certainly will go for 3mm, unless the panel is large and the extra strength of 4mm glass would be desirable. 

EDIT 2019-12-06:
I found some academic papers, free to download, that analyze glass thickness:

4mm, 4mm-two-layers, 4mm-two-layers-air-gap:

Comparing 4, 8, 12mm thickness:

Comparing 4, 5, 6mm thick:

3, 4, 5, 6mm low-iron:

...interesting, that last one determined that 4mm glass gave the highest output, not 3mm. They all obtained significant efficiency improvements going down to thinner glass, except for that last paper.

There is another consideration to improve efficiency: insulation thickness. My prototype has 35mm expanding foam under the basin floor, but tapering to 12mm at the back, and the wood side-walls are thin only 12mm. So, pretty obvious that this could be improved.

So, add this as item number 6:

  1. Thicker insulation

But how thick? This academic paper analyzes various thicknesses and different materials:
pdf d/l: depends on the material, but the ball-park figure they have got is 60mm thick is optimum, beyond which efficiency does not improve much. So, my prototype can be improved with thicker insulation. 

Tags: nomad

Testing basin-type solar distiller prototype-2

December 03, 2019 — BarryK

Today, Tuesday, December 3, 2019, Perth, Western Australia, it is mid-summer and the forecast is 39 degrees C, with scattered clouds. A good day to test the second prototype basin-type solar water distiller.

This distiller is pushing the limit of low angle for the glass, aiming for the narrowest possible design. The glass angle is 10 degrees and the depth of the distiller is 140mm -- well, kind of, it is constructed with 140x12mm pine on the sides.

Some posts on design and construction of the basin-type prototype #2:

So, 10 degree angle, white inside walls, how will it perform? The angle is probably going to be optimum in summer, and dismal in winter. Anyway, I set it up early this morning, around 7.30am. Initially in the shade of my garage. Orientation due North. Here it is, while still in shade:

img1 is sitting on a small camping table, but could have used any old cardboard box.

By 8.30am it was about 45% still shaded and hardly even warm.

8.45am: Sun just over entire panel. Sun intensity: 890 W/m2, ambient temperature 34 degrees C (yes, already hot!). Holding the IR meter about 3 inches above the glass, about 3/4 the way up, temperature is 32 degrees C, back side of the distiller is 32 degrees C. There is a slight breeze.

deg C
deg C
deg C



Official temp., via phone. Wind 24km/h
Only a very tiny amount of water out
Still not much water out
Some wispy clouds


Official temp., via phone, wind 13km/h
Lots of puffy clouds, ait mostly still or slight breeze

Moved the still slightly, facing sun at 1.00pm
Cloud cover increased, puffy clouds. Slight breeze


Official temp. Wind 24km/h
Clouds mostly gone
Blue sky, no clouds
No water coming out

Packed up at 5.45pm. Collected distilled water: 1.85 litres

The temperature readings of the glass are very high. This is obtained by pointing my IR meter at the glass, about 3 inches away, 3/4 of the way up. So it is not the inside temperature that is being measured, only an indication, and I think inside it would be even hotter.

So, my previous thinking that the inside of the distiller would not reach 80 degrees C was wrong, and I need to think carefully about what materials are used, that will retain integrity at that temperature.

The effective surface area of the glass is 0.652*0.542 which is 0.35 metre-squared.

How does this compare with the other distillers? I have not yet tested the F-Cubed C1000 distiller in mid-summer, only in winter, when I got 3.1 litres. So I will use the claimed mid-summer output, claimed by F-Cubed, which is 6 litres. That is a 1 metre-square panel.

Here is an earlier post discussing the claimed performance of the C1000 panel:

I am no longer going to compare by litres/hour, as the different designs work differently. The basin type is slow to get going in the morning, as it has to warm up, and internal stored heat may cause it to produce water a bit longer in the afternoon. This gives a different water output profile then the tilted wick-type, so it is simpler just to compare the total water produced in a day.

Another factor: with the sun oriented differently in the sky in mid-summer, the shade from my patio that came across the distiller late afternoon in the winter, can be avoided in mid-summer. meaning that today I got the sun on the distiller for more hours in the afternoon (albeit at an extreme angle).

Another note: I did move the distiller slightly, so as to avoid the afternoon shade from the patio, and also changed the orientation slightly, facing the sun at 1pm whereas before it was facing 12 noon. I probably should not have changed the orientation, even though only slight.

Normalizing the water output of my distiller, so as to compare with claimed output of the C1000:

1.85*(1/0.35) => 5.28 litres

That means my prototype #2 is 88% as efficient as the C1000 distiller!

I tested basin-type prototype #1 here:

Which produced 1.525 litres, though I did not leave it out quite so long in the afternoon, as it was not moved to avoid the afternoon shade. Prototype #1 has a larger piece of glass, 0.493 m2. Normalizing to compare with the F-Cubed:

1.525*(1/0.493) => 3.09 litres

Much less efficient. I wrote it down somewhere -- I think the glass angle was 35 degrees, rather high. Lots of side walls to loose heat. Interesting, the glass didn't get so hot.

Where to next? Enough prototypes! Basin-type prototype #2 has excellent efficiency, enough for me. The absolute efficiency of the C1000 is claimed to be 55%, so that means my prototype #2 is 0.88*55 => 48.4% -- that is very high for a basin-type.

I think that the "final design" needs a bigger glass angle, to perform better in winter, and I am thinking of 20 degrees. Also, the proportions of the glass can be changed, wider, less depth from front-to-back.

Tags: nomad