Re: [PATCH 1/2] PCI/MSI: Add MSIX option to write to ENTRY_DATA before any reads

On 11/18/24 00:48, dullfire@yahoo.com wrote:

From: Jonathan Currier dullfire@yahoo.com

Commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") introduces a readl() from ENTRY_VECTOR_CTRL before the writel() to ENTRY_DATA. This is correct, however some hardware, like the Sun Neptune chips, the niu module, will cause an error and/or fatal trap if any MSIX table entry is read before the corresponding ENTRY_DATA field is written to. This patch adds an optional early writel() in msix_prepare_msi_desc().

Why the issue can't be addressed into the relevant device driver? It looks like an H/W bug, a driver specific fix looks IMHO more fitting.

A cross subsystem series, like this one, gives some extra complication to maintainers.

Thanks,

Paolo