On Thu, Sep 05, 2013 at 11:44:36AM -0400, Tejun Heo wrote: > Given that multiple MSI is something which isn't too popular / already > superseded and that the condition is highly unlikely, do we really > care about possible partial success? This sort of interface is > unnecessarily complex and actively harmful. It forces all users to > wonder what could possibly happen and implement all sorts of nutty > fallback logic which is highly likely to be error-prone on both the > software and hardware side. Seriously, how much testing would such > code path would get both on the driver and firmware sides? > > It's an operation which isn't too likely to fail with a firm > known-to-work fallback. It's pointless and error-prone to try to > extract the last point zero zero one percent. I assume reasons for having this type of interface at the moment of taking design decision about pci_enable_msi_block() still hold true. I do not know what those reasons were, but I think the fact multiple MSIs are rarely used and MSI-X exists does not invalidate them now. I did consider the other argument - since pci_enable_msi_block_part() is explicitly provided with a value of MME the caller will not be satisfied with any other value and hence a repeated call with a lesser MME does not make sense for the caller. Therefore we could just fail in case the architecture returned a positive value. Same result, but different reasoning. At the moment I still prefer pci_enable_msi_block_part() to be similar to pci_enable_msi_block(). I do agree the fallback logic is error-prone, but I would not dare to scrap it all right away. Bjorn? > > Thanks. > > -- > tejun -- Regards, Alexander Gordeev agordeev@xxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
