mainlining shenanigans
1212bd821d
The irq_seqno_barrier is a tradeoff between doing work on every request (on the GPU) and doing work after every interrupt (on the CPU). We presume we have many more requests than interrupts! However, the current w/a for Ivybridge is an implicit delay that currently fails sporadically and consistently if we move the w/a into the irq handler itself. This makes the CPU barrier untenable for upcoming interrupt handler changes and so we need to replace it with a delay on the GPU before we send the MI_USER_INTERRUPT. As it turns out that delay is 32x MI_STORE_DWORD_IMM, or about 0.6us per request! Quite nasty, but the lesser of two evils looking to the future. Testcase: igt/gem_sync Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181228171641.16531-4-chris@chris-wilson.co.uk |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| 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 | ||
| 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.