d8efde3460
commit 754e449889b22fc3c34235e8836f08f51121d307 upstream. According to PCI 3.0 specification, sending both MSI and MSI-X interrupts is done by DWORD memory write operation to doorbell message address. The write operation for MSI has zero upper 16 bits and the MSI interrupt number in the lower 16 bits, while the write operation for MSI-X contains a 32-bit value from MSI-X table. Since the driver only uses interrupt numbers from range 0..31, the upper 16 bits of the DWORD memory write operation to doorbell message address are zero even for MSI-X interrupts. Thus we can enable MSI-X interrupts. Testing proves that kernel can correctly receive MSI-X interrupts from PCIe cards which supports both MSI and MSI-X interrupts. Link: https://lore.kernel.org/r/20220110015018.26359-13-kabel@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.