Z8530_READ_PORT(9) Internal Functions Z8530_READ_PORT(9)NAME
z8530_read_port - Architecture specific interface function
int z8530_read_port(unsigned long p);
port to read
Provided port access methods. The Comtrol SV11 requires no delays between accesses and uses PC I/O. Some drivers may need a 5uS delay
In the longer term this should become an architecture specific section so that this can become a generic driver interface for all
platforms. For now we only handle PC I/O ports with or without the dread 5uS sanity delay.
The caller must hold sufficient locks to avoid violating the horrible 5uS delay rule.
Alan Cox <firstname.lastname@example.org>
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 Z8530_READ_PORT(9)
Check Out this Related Man Page
drv_usecwait(9F) Kernel Functions for Drivers drv_usecwait(9F)NAME
drv_usecwait - busy-wait for specified interval
void drv_usecwait(clock_t microsecs);
Architecture independent level 1 (DDI/DKI).
microsecs The number of microseconds to busy-wait.
drv_usecwait() gives drivers a means of busy-waiting for a specified microsecond count. The amount of time spent busy-waiting may be
greater than the microsecond count but will minimally be the number of microseconds specified.
delay(9F) can be used by a driver to delay for a specified number of system ticks, but it has two limitations. First, the granularity of
the wait time is limited to one clock tick, which may be more time than is needed for the delay. Second, delay(9F) may only be invoked
from user context and hence cannot be used at interrupt time or system initialization.
Often, drivers need to delay for only a few microseconds, waiting for a write to a device register to be picked up by the device. In this
case, even in user context, delay(9F) produces too long a wait period.
drv_usecwait() can be called from user or interrupt context.
SEE ALSO delay(9F), timeout(9F), untimeout(9F)
Writing Device Drivers
The driver wastes processor time by making this call since drv_usecwait() does not block but simply busy-waits. The driver should only make
calls to drv_usecwait() as needed, and only for as much time as needed. drv_usecwait() does not mask out interrupts.
SunOS 5.10 12 Nov 1992 drv_usecwait(9F)
I know the following questions are noobish questions but I am asking them because I am confused about the basics of history behind UNIX and LINUX.
Ok onto business, my questions are-:
Was/Is UNIX ever an open source operating system ?
If UNIX was... (21 Replies)
Hello and thanks in advance for any help anyone can offer me
I'm trying to learn the find command and thought I was understanding it... Apparently I was wrong. I was doing compound searches and I started getting weird results with the -size test. I was trying to do a search on a 1G file owned by... (14 Replies)
i have installed quota on my centos 7 machine and its what im after (setting size limit on users, so they cant fill the hard drive)
i want to now make this part of my create user script for my sftp server so i want to do a echo and a read command so i capture the limit they enter... (0 Replies)
I need to write a shell script which opens a file and increments the version(text) within the file every time the script runs. For example:
$ cat docker_file.yml
So, I would like... (6 Replies)
We use DB2 v10.5 and using DBArtisan tool
Can someone please guide how to convert digits to binary numbers using db2 feature.
Ex> for number 9 , binary should be 1001 ( 8+1)
Any help appreciated. Thanks (2 Replies)
how to using tar with exclude directory and compress it using tar.Z
i only know how to exclude dir only with this command below:
tar -cvf /varios/restore/test.tar -X excludefile.txt /jfma/test1/
how to compress it using 1 command?
Please use CODE tags as... (6 Replies)
Quite an obscure question I think.
We have a rebuild process for remote sites that allows us to PXE rebuild a till (actually a PC with a touch screen and various fancy bits) running CentOS. The current CentOS5 tills work just fine with a tar image restore and some personalisation. Sadly,... (4 Replies)
I had recently learnt a bit of Docker(which provides containerization process).
Here are some of my learning points from it.
Let us start first with very basic question:
What is Docker:
Docker is a platform for sysadmins and developers to DEPLOY, DEVELOP and RUN applications ... (7 Replies)
What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend (3 Replies)
Hello... And thanks in advance for any help anyone can offer me
I was trying to work out the differences between displaying modify, access, and change times with the 'ls' command. Everything seems in order when I look at files, but the access time on a directory doesn't seem to change when I... (4 Replies)
I am having an issue here with CentOS release 6.6 (Final) that shows all of the space used up, but I can't tell where the space went.
Seemingly I am using up 100%, according to
Filesystem Size Used Avail Use% Mounted on... (27 Replies)
I'm trying to use a bash script for a psych experiment that involves listening to sound files and responding. If I have something like the code below, how can I make sure that a key press is assigned to RESPONSE only after the second echo statement?
for i in 1 2 3; do
... (10 Replies)
After the success of the jq - tool for parsing and manipulating JSON-Data someone wrote a tool called yq, which aims to be the same for YAML, what jq is for JSON. Seems to work fine. I'll definitely give it a chance in future.
... (1 Reply)
I am very pleased to announce that Dave Munro (gull04) is joining the Moderation Team, after being a very valuable member of UNIX.com for 15+ years.
Dave is an IT Consultant with 30 years of experience this year, has worked in many of the industry vertical market segments and has... (6 Replies)