[Bug 620296] [NEW] Serialports behave strange using blocking IO

[Søren Holm]

Public bug reported:

Normally when executing "cat /dev/ttyS0" to read in from a comport cat
will block when it reads the port. The behavior I am seing is that it
just exist without reading anything.

The read from the port I have to add O_NDELAY to the open-call. The
problem is that 'read' way ends up being a non-blocking which is not
what I want.

A simmilar error occurs when execution "cat /dev/ttyUSB0" to read from
my pl2303 usb2serial adapter. This time it is just the 'opan'-call that
blocks forever.

Can anyone please confirm this behavior.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: linux-image-2.6.35-15-generic 2.6.35-15.21
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.35-15.21-generic 2.6.35.1
Uname: Linux 2.6.35-15-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: amd64
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  sgh        1884 F.... kmix
 /dev/snd/controlC1:  sgh        1884 F.... kmix
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0640000 irq 46'
   Mixer name	: 'Realtek ALC262'
   Components	: 'HDA:10ec0262,10cf0000,00100002 HDA:11c11040,11c10001,00100200'
   Controls      : 28
   Simple ctrls  : 17
Card1.Amixer.info:
 Card hw:1 'Headset'/'Logitech Logitech USB Headset at usb-0000:00:1d.7-4.4, full speed'
   Mixer name	: 'USB Mixer'
   Components	: 'USB046d:0a0c'
   Controls      : 6
   Simple ctrls  : 2
Date: Thu Aug 19 08:41:46 2010
HibernationDevice: RESUME=UUID=6aaf5bbe-894e-4d6a-a25b-2525d19bd771
InstallationMedia: Kubuntu 10.10 "Maverick Meerkat" - Alpha amd64 (20100729)
MachineType: FUJITSU SIEMENS LIFEBOOK E8110
PccardctlIdent:
 Socket 0:
   no product info available
 Socket 1:
   product info: "O2Micro", "SmartCardBus Reader", "V1.0", ""
   manfid: 0xffff, 0x0001
PccardctlStatus:
 Socket 0:
   no card
 Socket 1:
   5.0V 16-bit PC Card
   Subdevice 0 (function 0) [unbound]
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.35-15-generic root=UUID=89d48ce8-f46c-40f0-a2b2-c0cdbaff07cb ro quiet splash
ProcEnviron:
 LANGUAGE=da_DK
 PATH=(custom, user)
 LANG=da_DK.utf8
 SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.38
RfKill:
 0: phy0: Wireless LAN
 	Soft blocked: no
 	Hard blocked: yes
SourcePackage: linux
dmi.bios.date: 12/21/2006
dmi.bios.vendor: FUJITSU // Phoenix Technologies Ltd.
dmi.bios.version: Version 1.19
dmi.board.name: FJNB1AF
dmi.board.vendor: FUJITSU
dmi.board.version: CP322567-02
dmi.chassis.type: 10
dmi.chassis.vendor: FUJITSU SIEMENS
dmi.chassis.version: E8110
dmi.modalias: dmi:bvnFUJITSU//PhoenixTechnologiesLtd.:bvrVersion1.19:bd12/21/2006:svnFUJITSUSIEMENS:pnLIFEBOOKE8110:pvr:rvnFUJITSU:rnFJNB1AF:rvrCP322567-02:cvnFUJITSUSIEMENS:ct10:cvrE8110:
dmi.product.name: LIFEBOOK E8110
dmi.sys.vendor: FUJITSU SIEMENS

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug filesystem maverick needs-upstream-testing regression-proposed

-- 
Serialports behave strange using blocking IO
https://bugs.launchpad.net/bugs/620296
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