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!)
e1fa076706
There is a timing issue captured during ishtp client sending stress tests. It was observed during stress tests that ISH firmware is getting out of ordered messages. This is a rare scenario as the current set of ISH client drivers don't send much data to firmware. But this may not be the case going forward. When message size is bigger than IPC MTU, ishtp splits the message into fragments and uses serialized async method to send message fragments. The call stack: ishtp_cl_send_msg_ipc->ipc_tx_callback(first fregment)-> ishtp_send_msg(with callback)->write_ipc_to_queue-> write_ipc_from_queue->callback->ipc_tx_callback(next fregment)...... When an ipc write complete interrupt is received, driver also calls write_ipc_from_queue->ipc_tx_callback in ISR to start sending of next fragment. Through ipc_tx_callback uses spin_lock to protect message splitting, as the serialized sending method will call back to ipc_tx_callback again, so it doesn't put sending under spin_lock, it causes driver cannot guarantee all fragments be sent in order. Considering this scenario: ipc_tx_callback just finished a fragment splitting, and not call ishtp_send_msg yet, there is a write complete interrupt happens, then ISR->write_ipc_from_queue ->ipc_tx_callback->ishtp_send_msg->write_ipc_to_queue...... Because ISR has higher exec priority than normal thread, this causes the new fragment be sent out before previous fragment. This disordered message causes invalid message to firmware. The solution is, to send fragments synchronously: Use ishtp_write_message writing fragments into tx queue directly one by one, instead of ishtp_send_msg only writing one fragment with completion callback. As no completion callback be used, so change ipc_tx_callback to ipc_tx_send. Signed-off-by: Even Xu <even.xu@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| 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.