Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices:
OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
Call skb_tx_timestamp() within can_put_echo_skb() so that a software tx
timestamp gets attached to the skb.
There two main reasons to include this call in can_put_echo_skb():
* It easily allow to enable the tx timestamp on all devices with
just one small change.
* According to Documentation/networking/timestamping.rst, the tx
timestamps should be generated in the device driver as close as possible,
but always prior to passing the packet to the network interface. During the
call to can_put_echo_skb(), the skb gets cloned meaning that the driver
should not dereference the skb variable anymore after can_put_echo_skb()
returns. This makes can_put_echo_skb() the very last place we can use the
skb without having to access the echo_skb[] array.
Remark: by default, skb_tx_timestamp() does nothing. It needs to be activated
by passing the SOF_TIMESTAMPING_TX_SOFTWARE flag either through socket options
or control messages.
References:
* Support for the error queue in CAN RAW sockets (which is needed for
tx timestamps) was introduced in:
https://git.kernel.org//torvalds/c/eb88531bdbfaafb827192d1fc6c5a3fcc4fadd96
* Put the call to skb_tx_timestamp() just before adding it to the
array:
https://lore.kernel.org/r/043c3ea1-6bdd-59c0-0269-27b2b5b36cec@victronenergy.com
* About Tx hardware timestamps
https://lore.kernel.org/r/20210111171152.GB11715@hoboy.vegasvil.org
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20210112095437.6488-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.