Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[intelxl] Choose to operate in non-PXE mode
The physical function defaults to operating in "PXE mode" after a power-on reset. In this mode, receive descriptors are fetched and written back as single descriptors. In normal (non-PXE mode) operation, receive descriptors are fetched and written back only as complete cachelines unless an interrupt is raised. There is no way to return to PXE mode from non-PXE mode, and there is no way for the virtual function driver to operate in PXE mode. Choose to operate in non-PXE mode. This requires us to trick the hardware into believing that it is raising an interrupt, so that it will not defer writing back receive descriptors until a complete cacheline (i.e. four packets) have been consumed. We do so by configuring the hardware to use MSI-X with a dummy target location in place of the usual APIC register. Signed-off-by: Michael Brown <mcb30@ipxe.org>
- Loading branch information
Showing
2 changed files
with
155 additions
and
28 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters