Messages in this thread |  | | | Subject | Re: [PATCH] ALSA: hda-intel - Disable MSI support by default | | From | Benjamin Herrenschmidt <> | | Date | Wed, 15 Nov 2006 15:01:00 +1100 |
| |
> If you take an INTX interrupt, it's over a pin on the motherboard and > thus can arrive before the DMA makes it to main memory, so you have to > have all of this fixup logic to handle that case and you don't even > know the interrupt is really for you so you have to actually check > the status block.
Out of curiosity. Are you sure there is no case of stupid bridge converting the MSI into some APIC/whatever interrupt for the CPU potentially before all previous DMA have been fully pushed to the coherent domain (still in some internal store queue for example) ?
I suppose the Intel bridges get it right since they pretty much defined them in the first place... but my experience with chipset designers is that they have generally little regard for ordering issues (and the impact those have on software) and no clue about anything related to interrupt issues.
Ben.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |