Many other modules might trigger ACPI device registration. This means the the basic ACPI subsystem has to be up and available before much of the Hardware is usable. Hence, we can see that the ACPI subsystem gets registered here. What I am not certain of is when does this code get called?
Continue readingAs I found out after I posted my lat entry , the correct way to find the Root pointer for the ACPI tables is to get it from the EFI System table. Where does that get set? Here’s the general flow: again, we start at init/main.c. start_kernel. However, the call is not in the ACPI code, but rather in setup_arch. The call chain goes
start-Kernel->setup_arch->efi_init->efi_get_fdt_params and that seems to pull it our of initial_boot_params. I can’t quite see where that is initialized. Yet. From context it looks like it is constructed out of the kernel command line parameters. Still learning….
Last article got up through allocating the memory for the ACPI Tables. Now we want to populate them.
Continue readingIt started as a request from our tech lead: please help triage these patches. So I lookedat the set of patches and started with what looked like the simplest one:
Fix topology for Core scheduling.
It *just* reorders the code to call
store_cpu_topology(cpu);
before
notify_cpu_starting() .
Yeah…there is no such thing as a simple patch. These are my notes as I study and learn ACPI. My assumptions are here for all to see, and may well prove to be wrong.
Lets dig in.
Continue readingI want to call out a stellar article that told me exactly what I needed to do in order to use virt-install and cloud-init to launch a cloud-image. The only thing I have to add is the caveat that the #cloud-config comment at the top of the user-data file is required. The system will ignore the file if it does not start with that comment. This is the easiest way I know to launch a brand new VM.
The following xmllint XPath query will pull out the name of the backing file for a VM named fedora-server-36 and an external snapshot named fedora-36-post-install,
virsh snapshot-dumpxml fedora-server-36 fedora-server-36-post-install | xmllint --xpath "string(//domainsnapshot/disks/disk[@snapshot='external']/source/@file)" - |
The string function extracts the attribute value.
This value can be used in the process of using or deleting the snapshot.
I had a bug in my OpenGL program. Here was the original code:
for (Orbitor o : orbitors){ o.calculate_position(); } |
and here was the working version
for (std::vector<Orbitor>::iterator it = orbitors.begin() ; it != orbitors.end(); ++it) { it->calculate_position(); } |
The processes of development, installation, testing, and debugging of software all benefit from the use of a virtual machines. If you are working in a Linux based infrastructure, you have access to the virtual machine management on your system. There are a handful of related technologies that all work together to help you get your work done.
Continue readingNow that I can build my app with Autotools, I want to make it work with conan. In my head, I have conan mapped to projects like cargo in rust and pip in Python. However, C++ has a far less homogenized toolchain, and I expect things are going to be more “how to make it work for you.” I started with Autotools to minimize that.
Continue reading