On Fri, Jan 13, 2012 at 12:59 PM, Stanislaw Gruszka <sgruszka@xxxxxxxxxx> wrote: > Same devices can generate interrupt without properly setting bit in > INT_SOURCE_CSR register (spurious interrupt), what will cause IRQ line > will be disabled by interrupts controller driver. > > We discovered that clearing INT_MASK_CSR stops such behaviour. We > previously first read that register, and then clear all know interrupt > sources bits and do not touch reserved bits. After this patch, we write > to all register content (I believe writing to reserved bits on that > register will not cause any problems, I tested that on my rt2800pci > device). > > This fix very bad performance problem, practically making device > unusable (since worked without interrupts), reported in: > https://bugzilla.redhat.com/show_bug.cgi?id=658451 > > We previously tried to workaround that issue in commit > 4ba7d9997869d25bd223dea7536fc1ce9fab3b3b "rt2800pci: handle spurious > interrupts", but it was reverted in commit > 82e5fc2a34fa9ffea38f00c4066b7e600a0ca5e6 > as thing, that will prevent to detect real spurious interrupts. > > Reported-and-tested-by: Amir Hedayaty <hedayaty@xxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> > --- > drivers/net/wireless/rt2x00/rt2800pci.c | 28 ++++++++-------------------- > 1 files changed, 8 insertions(+), 20 deletions(-) > > diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c > index 4941a1a..dc88bae 100644 > --- a/drivers/net/wireless/rt2x00/rt2800pci.c > +++ b/drivers/net/wireless/rt2x00/rt2800pci.c > @@ -422,7 +422,6 @@ static int rt2800pci_init_queues(struct rt2x00_dev *rt2x00dev) > static void rt2800pci_toggle_irq(struct rt2x00_dev *rt2x00dev, > enum dev_state state) > { > - int mask = (state == STATE_RADIO_IRQ_ON); > u32 reg; > unsigned long flags; > > @@ -436,25 +435,14 @@ static void rt2800pci_toggle_irq(struct rt2x00_dev *rt2x00dev, > } > > spin_lock_irqsave(&rt2x00dev->irqmask_lock, flags); > - rt2x00pci_register_read(rt2x00dev, INT_MASK_CSR, ®); > - rt2x00_set_field32(®, INT_MASK_CSR_RXDELAYINT, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_TXDELAYINT, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_RX_DONE, mask); > - rt2x00_set_field32(®, INT_MASK_CSR_AC0_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_AC1_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_AC2_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_AC3_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_HCCA_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_MGMT_DMA_DONE, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_MCU_COMMAND, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_RXTX_COHERENT, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_TBTT, mask); > - rt2x00_set_field32(®, INT_MASK_CSR_PRE_TBTT, mask); > - rt2x00_set_field32(®, INT_MASK_CSR_TX_FIFO_STATUS, mask); > - rt2x00_set_field32(®, INT_MASK_CSR_AUTO_WAKEUP, mask); > - rt2x00_set_field32(®, INT_MASK_CSR_GPTIMER, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_RX_COHERENT, 0); > - rt2x00_set_field32(®, INT_MASK_CSR_TX_COHERENT, 0); > + reg = 0; > + if (state == STATE_RADIO_IRQ_ON) { > + rt2x00_set_field32(®, INT_MASK_CSR_RX_DONE, 1); > + rt2x00_set_field32(®, INT_MASK_CSR_TBTT, 1); > + rt2x00_set_field32(®, INT_MASK_CSR_PRE_TBTT, 1); > + rt2x00_set_field32(®, INT_MASK_CSR_TX_FIFO_STATUS, 1); > + rt2x00_set_field32(®, INT_MASK_CSR_AUTO_WAKEUP, 1); > + } > rt2x00pci_register_write(rt2x00dev, INT_MASK_CSR, reg); > spin_unlock_irqrestore(&rt2x00dev->irqmask_lock, flags); Looks good to me. Thanks for finding the root cause for this issue! Helmut -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
