Saturday, June 26, 2021

логическая загадка

Есть 5 космических кораблей (из разных стран мира). У каждого есть номер (1-5), цвет, маскот и каждый привозит сувенир из Луны. Они не стартуют в своей стране но приземляются в ней.  Нам известны следующие факты: 


  1. Синий корабль стартует в Хирошиме (Япония)
  2. Русский корабль привезёт с Луны "флаг США" (как сувенир) 
  3. В Люнбурге (в каком же государстве ... дочитать до конца и узнаешь) стартует корабль номер 1. 
  4. Кошка путешествует в корабле с номером на 1 меньше чем номер золотого корабля. 
  5. Соловей является маскотом корабля, с номером на 1 больше чем у зелёного корабля. 
  6. Корабль со средним номером привозит "лунарный пыл" (как сувенир). 
  7. Улитка маскот корабля, который стартует на Байконуре (будем считать городом в России). 
  8. Корабль который стартовал на мысе Каневерале (США) привезет "старую лунарную камеру" (=сувенир). 
  9. Маскотом на красном корабле является жаба. 
  10. Зелённый корабль принадлежит Китае. 
  11. У Японии номер 2. 
  12. Серебристый корабль принадлежит Германии. 
  13. Корабль США стартует в Пекинге. 
  14. Германия привезёт в Люнбург с Луны "космическоя авто" и имеет номер на 1 меньше чем Россия. 


Вся эта информация хватит для того, чтобы ответить на следующие 2 вопроса:

  1. A. Который корабль имеет зебру как маскота? 
  2. B. Который корабль привезёт "женшину" как сувенир?

Tuesday, March 16, 2021

 Working on Proof-of-concept

Based on my git segments/sums, I can construct a 

poset of modifications (micro-features), and 

study them in isolation. For the whole-picture study I use (modified) xdot with an extension to handle "gitk://" actions, so I can open gitk (restricted to the segment history) by clicking on single nodes:

git-hierarchy contains the "git-graph -x" command to open such a graph.

Monday, September 11, 2017

Keeping up with debian Sid

My small build system

I need to replace some distro packages with my improvements.
For this I need to patch the sources -- I only handle git. I need to be notified, warned, when a new version is needed.

So I patched apt to report when a switch from my version to the upstream would happen (due to  "apt dist-upgrade").

In such a case I run my  git-rebase-origin which rebases my feature poset (of feature branches/segments mixed into "merges") over a refreshed remote branch.

Then I run my scripts to invoke gbp(1) with a suitable version string, and create the deb packages & put them in reprepro.

the sequence of commands to maintain apt itself:

$ cd ~/git/apt/
$ git-rebase-origin  

# this deduces the upstream -- base of my feature branches.

$ release
# this detects I'm building my extension of upstream debian package, so deduces the correct version, build, uploads, tags, pushes, installs.

When I only want to test some changes, I run 
$ snap
which creates a .deb package, installs it, withouth any reprepro etc.

Sunday, July 16, 2017

Logický test

5 lodí, každá má číslo, barvu, maskota a suvenýr z Měsíce.
Nestartují ze své země, ale přistávají v ní.

1. Modrá loď startuje v Hirošimě
2. SSSR přiveze z Měsíce vlajku USA
3. v Lunburgu startuje loď s číslem 1.
4. Kočka cestuje v lodi s číslem o 1 menším než je číslo zlaté lodi.
5 Slavík je maskotem lodi, jejíž start. číslo je o 1 vyšší než číslo zelené lodi.
6 Loď s prostředním číslem veze zpět měsíční prach.
7 Hlemýžd je maskot lodi, jež startuje na Bajkonuru.
8 Stát, který odstartoval na mysu Caneveral, příveze zpět starou měsíční kameru.
9 Maskot v červené lodi je žába.
10 Zelená loď patří Číně.
11 Japonsko má startovní číslo 2.
12 Stříbrná loď patří NSR.
13 Loď USA startuje v Pekingu.
14 NSR přiveze do Lunburgu z měsíce kosmické auto a má startovní číslo o 1 nižší než SSSR.

Tyto infomace stačí k tomu, abychom zodpověděli dvě otázky:

A. Která loď má jako maskota zebru?
B. Která loď přiveze zpět z měsíce ženu?

Monday, May 29, 2017

Upgrading Nubia 7 mini

I recently bought this  phone on marktplaats, already upgraded to Mokee Android 7. I liked the features, my previous phone used Android 4.2.
So I bought another one for my wife, this time I had to make the upgrade myself. It was not straightforward:

The first nubia used as recovery  TWRP 3.0.2-0, the other is with clockwork-mod (v6.0.5.0).
  • I had to resize the big "grow" partition manually, i.e. merge it with "userdata".
  • suddenly I saw disconnections of Wifi, and that was due to the same MAC address of the 2 nubias.

MAC address

So I searched for a solution to tune the MAC address. I found the hint on Intf0MacAddress in WCNSS_qcom_cfg.ini. But it did not work.
/data/misc/wifi/WCNSS_qcom_cfg.ini  nor  /system/etc/wifi/WCNSS_qcom_cfg.ini
So I had a workaround to
echo 98:6c:f5:63:ec:d0 > /sys/devices/fb000000.qcom,wcnss-wlan/wcnss_mac_addr
while in airplane mode.
In the end I  found /persist/WCNSS_qcom_cfg.ini which indeed works, and overrides the other 2 files.

ANDROID_SERIAL to distinguish them?

To have them accessible via adb at the same time, I need to distinguish by this serial number, which is unfortunately identical. For now I overwrite the kernel cmdline in img_info with "androidboot.serialno=XXX"

Proximity sensor

After receiving some (whatsapp) calls, I noticed it was almost impossible to get the screen back on, as expected.

So, as a workaround I turned off  in Phone> Settings> Accessibility> Use proximity sensor.
But Whatsapp does not seem to have this option.

So I installed Sensors test and some app to "reset/calibrate" but to no effect.

So I started to look for the kernel driver, to fix a possible bug. There are confusingly multiple kernel sources on github:
Btw. failures of the other kernels can be seen thanks to android ram-console: after the failure, the phone reboots to recovery and 
adb shell cat /proc/last_kmsg
shows the problem.

In the end the problems is only the calibration, so 
 echo 500 > prox_threshold_low  
fixes the issue. To see this value, I did:
cd /sys/class/proximity/proximity/
echo 1 > prox_debug
and "dmesg -c" while running the sensor test app, to see:

[43580.286869] [SENSOR_ALS_PROX] [taos_prox_threshold_set: 2338] proxdata = 396
I guess it's stored in /persist/proxdata/threshold ?

Other issues

calendar/alarm database -- crash when entering the Alarm app:

android.database.sqlite.SQLiteException: Can't downgrade database from version 12 to 8

I removed the relevant file.

SystemUI crash due to wallpaper using too big image

java.lang.RuntimeException: Canvas: trying to draw too large(143769600bytes) bitmap.
AppCrashReceiver: stopped unexpectedly...

rm  /data/system/user/0/wallpaper_*

My improvements (divided into feature-segments)

Saturday, November 26, 2016

Taming Android am command

In Android an intent can carry data of a certain mime type.
To test this feature, I had an App which sets up an IntentFilter, and then I would manually trigger it:

am broadcast -t text/xml -a my.action.START -d "file:///system/usr/share/mmc/settings.xml"

It did not work, so I had to read better about am options:

So I learned about FLAG_DEBUG_LOG_RESOLUTION (I also saw it in the sources). So I added "-t 8" as option.
Then I saw that the type used during the matching was Null, so I verified the binder transaction code:reading from binder tx data and writing tx data Here the writing:

intent.writeToParcel(data, 0); // serializes the Intent
data.writeString(resolvedType); // separately adds the type

So the type has to be delivered separately, but am does not do it:

private void sendBroadcast() throws Exception {
Intent intent = makeIntent(UserHandle.USER_CURRENT);
IntentReceiver receiver = new IntentReceiver();
System.out.println("Broadcasting: " + intent);
// this is the fix null -> intent.getType()
mAm.broadcastIntent(null, intent, /* null */ intent.getType(), receiver, 0, null, null, mReceiverPermission,, true, false, mUserId);

Thursday, October 16, 2014

Building the Forking X server

Building the Forking X server

I work on Debian (Sid), so the Git repositories contain debian/ and  packages are built by git-buildpackage as documented in another post.

You can also install by using my debian repository:
deb sid main

I did not implement a new Extension - I extended the protocol of XKB.
So, first build the x11proto-kb-dev package
Now it's possible to build both libX11 and the server:
Since the ABI between the server and "input device" driver, it's necessary to recompile them. I use only evdev & synaptics. But, evdev is used for the keyboard, and I need precise timestamps, so there are changes, hence build from this repo:
At this point the Xserver could be restarted. After building the X11 from:

    one can start asking the X server about the active plugins. There is a tool for that:
At this point it is possible to:
$ xinput list
....Virtual core keyboard                       id=3    [master keyboard (2)]
$  xplugin -l -d 3  
3 plugins in the pipeline
1: never-freeze-queue
2: xkb-auto-repeat
0: core

The function of each plugin:  

never-freeze-queue collects events while waiting for following plugins to proceed (& accept the events).  xkb-auto-repeat generates the auto-repeat events, core is the interface with dix/events.c.

Now we can finaly build the interesting feature: the "fork" plugin to be inserted before the auto-repeat plugin. It is implemented in C++ which explains some effort in the X server and x11proto-kb sources to make them C++ compatible.
so after building (& installing) you can insert that plugin:
xplugin -d 3 fork       # 3 is still the id of keyboard.
or also remove it:
$ xplugin -d 3 -fork

Now to activate some of the forks we need to communicate with that plugin, 
and build up a language to express the configuration.
For the configuration language, I chose to use Scheme, in the Gauche implementation. So, one needs to install Gauche-dev, and build this binding module:
building that one is more involved (see my blog about building Gauche modules).

That packages contains my configuration to be used this way:
$ fork-config-mmc.scm 3

When trying to configure, keep in mind, that allocation of the "fork" keycodes
is possible only if the XKB Geometry allows it. I.e. keycodes not found on the Geometry will be used.

See in how key "f" is used as Hyper modifier, or how Meta key acts as Escape key.