On Fri, Nov 07, 2008 at 08:53:49AM +0000, Jan Beulich wrote: > msix_flush_writes() is being called exclusively after calling msi_set_mask_bit(), > and that function already does follow writel() by readl() in the MSI-X case. Yes - this part is correct. If you care to split this into seperate parts, please add: Reviewed-by: Grant Grundler <grundler@xxxxxxxxxxxxxxxx> for this chunk. > Also, isn't the single use of multi_msi_capable() broken (in the event that > the Multiple Message Capable field was 5, the shift would be undefined, > on x86 in particular would yield 1 as the result, where 0 would be needed), > and the subsequent twiddling of temp needlessly complicated (subtracting > one should be sufficient here). Comment on this chunk below. > And isn't multi_msi_enable(), though unused (since msi_{en,dis}able() are > unused), broken altogether (shifting num right by 1 instead of taking the > binary log)? > > In case so: > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx> > > --- > drivers/pci/msi.c | 30 ++---------------------------- > drivers/pci/msi.h | 2 +- > 2 files changed, 3 insertions(+), 29 deletions(-) > > --- linux-2.6.28-rc3/drivers/pci/msi.c 2008-11-03 15:53:11.000000000 +0100 > +++ 2.6.28-rc3-pci-msi-misc/drivers/pci/msi.c 2008-11-07 09:11:36.000000000 +0100 > @@ -103,29 +103,6 @@ static void msix_set_enable(struct pci_d > } > } > > -static void msix_flush_writes(unsigned int irq) > -{ > - struct msi_desc *entry; > - > - entry = get_irq_msi(irq); > - BUG_ON(!entry || !entry->dev); > - switch (entry->msi_attrib.type) { > - case PCI_CAP_ID_MSI: > - /* nothing to do */ > - break; > - case PCI_CAP_ID_MSIX: > - { > - int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE + > - PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET; > - readl(entry->mask_base + offset); > - break; > - } > - default: > - BUG(); > - break; > - } > -} > - > /* > * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to > * mask all MSI interrupts by clearing the MSI enable bit does not work > @@ -255,13 +232,11 @@ void write_msi_msg(unsigned int irq, str > void mask_msi_irq(unsigned int irq) > { > msi_set_mask_bits(irq, 1, 1); > - msix_flush_writes(irq); > } > > void unmask_msi_irq(unsigned int irq) > { > msi_set_mask_bits(irq, 1, 0); > - msix_flush_writes(irq); > } > > static int msi_free_irqs(struct pci_dev* dev); > @@ -389,9 +364,8 @@ static int msi_capability_init(struct pc > pci_read_config_dword(dev, > msi_mask_bits_reg(pos, entry->msi_attrib.is_64), > &maskbits); > - temp = (1 << multi_msi_capable(control)); > - temp = ((temp - 1) & ~temp); > - maskbits |= temp; > + temp = 1U << (multi_msi_capable(control) - 1); > + maskbits |= (temp << 1) - 1; Isn't this the new code the same as: maskbits |= (1U << multi_msi_capable(control)) - 1; So the "& ~temp" got dropped...which looks correct to me. "& ~temp" isn't needed given only one bit could be set in temp. In any case, I'm feeling a bit dense since I'm not seeing the problem. If multi_msi_capable(control) is 5, how is the shift of a signed int ("1") undefined? control is u16 and temp is "unsigned int" if that matters. > pci_write_config_dword(dev, entry->msi_attrib.is_64, maskbits); > entry->msi_attrib.maskbits_mask = temp; > } > --- linux-2.6.28-rc3/drivers/pci/msi.h 2007-02-04 19:44:54.000000000 +0100 > +++ 2.6.28-rc3-pci-msi-misc/drivers/pci/msi.h 2008-11-07 09:13:09.000000000 +0100 > @@ -23,7 +23,7 @@ > #define multi_msi_capable(control) \ > (1 << ((control & PCI_MSI_FLAGS_QMASK) >> 1)) > #define multi_msi_enable(control, num) \ > - control |= (((num >> 1) << 4) & PCI_MSI_FLAGS_QSIZE); > + control |= ((ilog2(num) << 4) & PCI_MSI_FLAGS_QSIZE) I've no clue what the issue is here. Can you point at a section in the PCI sec that defines this? thanks, grant > #define is_64bit_address(control) (!!(control & PCI_MSI_FLAGS_64BIT)) > #define is_mask_bit_support(control) (!!(control & PCI_MSI_FLAGS_MASKBIT)) > #define msi_enable(control, num) multi_msi_enable(control, num); \ > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html