01f648202c
On GFX9.4.1, the implicit wait count instruction on s_barrier is disabled by default in the driver during normal operation for performance requirements. There is a hardware bug in GFX9.4.1 where if the implicit wait count instruction after an s_barrier instruction is disabled, any wave that hits an exception may step over the s_barrier when returning from the trap handler with the barrier logic having no ability to be aware of this, thereby causing other waves to wait at the barrier indefinitely resulting in a shader hang. This bug has been corrected for GFX9.4.2 and onward. Since the debugger subscribes to hardware exceptions, in order to avoid this bug, the debugger must enable implicit wait count on s_barrier for a debug session and disable it on detach. In order to change this setting in the in the device global SQ_CONFIG register, the GFX pipeline must be idle. GFX9.4.1 as a compute device will either dispatch work through the compute ring buffers used for image post processing or through the hardware scheduler by the KFD. Have the KGD suspend and drain the compute ring buffer, then suspend the hardware scheduler and block any future KFD process job requests before changing the implicit wait count setting. Once set, resume all work. Signed-off-by: Jonathan Kim <jonathan.kim@amd.com> Reviewed-by: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.