mainlining shenanigans
083874549f
On 38+ Intel-based ASUS products, the NVIDIA GPU becomes unusable after S3
suspend/resume. The affected products include multiple generations of
NVIDIA GPUs and Intel SoCs. After resume, nouveau logs many errors such
as:
fifo: fault 00 [READ] at 0000005555555000 engine 00 [GR] client 04
[HUB/FE] reason 4a [] on channel -1 [007fa91000 unknown]
DRM: failed to idle channel 0 [DRM]
Similarly, the NVIDIA proprietary driver also fails after resume (black
screen, 100% CPU usage in Xorg process). We shipped a sample to NVIDIA for
diagnosis, and their response indicated that it's a problem with the parent
PCI bridge (on the Intel SoC), not the GPU.
Runtime suspend/resume works fine, only S3 suspend is affected.
We found a workaround: on resume, rewrite the Intel PCI bridge
'Prefetchable Base Upper 32 Bits' register (PCI_PREF_BASE_UPPER32). In the
cases that I checked, this register has value 0 and we just have to rewrite
that value.
Linux already saves and restores PCI config space during suspend/resume,
but this register was being skipped because upon resume, it already has
value 0 (the correct, pre-suspend value).
Intel appear to have previously acknowledged this behaviour and the
requirement to rewrite this register:
https://bugzilla.kernel.org/show_bug.cgi?id=116851#c23
Based on that, rewrite the prefetch register values even when that appears
unnecessary.
We have confirmed this solution on all the affected models we have in-hands
(X542UQ, UX533FD, X530UN, V272UN).
Additionally, this solves an issue where r8169 MSI-X interrupts were broken
after S3 suspend/resume on ASUS X441UAR. This issue was recently worked
around in commit
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| firmware | ||
| 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 | ||
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| 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.