Re: [PATCH 04/10] rt2800: do not overwrite WPDMA_GLO_CFG_WP_DMA_BURST_SIZE

[Stanislaw Gruszka <sgruszka@xxxxxxxxxx>]

On Sat, Nov 05, 2016 at 01:55:14PM +0100, Mathias Kresin wrote:
> 02.11.2016 15:10, Stanislaw Gruszka:
> >We already initlized WPDMA_GLO_CFG_WP_DMA_BURST_SIZE to 3 on
> >rt2800_init_registers().
> >
> >Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
> >---
> > drivers/net/wireless/ralink/rt2x00/rt2800lib.c |    1 -
> > 1 files changed, 0 insertions(+), 1 deletions(-)
> >
> >diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> >index feceb13..9ecdc4c 100644
> >--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> >+++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> >@@ -6756,7 +6756,6 @@ int rt2800_enable_radio(struct rt2x00_dev *rt2x00dev)
> > 	rt2800_register_read(rt2x00dev, WPDMA_GLO_CFG, &reg);
> > 	rt2x00_set_field32(&reg, WPDMA_GLO_CFG_ENABLE_TX_DMA, 1);
> > 	rt2x00_set_field32(&reg, WPDMA_GLO_CFG_ENABLE_RX_DMA, 1);
> >-	rt2x00_set_field32(&reg, WPDMA_GLO_CFG_WP_DMA_BURST_SIZE, 2);
> 
> More a notice than a potential issue since I don't have much
> knowledge about the driver/chip internals.
> 
> But WPDMA_GLO_CFG_WP_DMA_BURST_SIZE in rt2800_init_registers() is
> set conditionally for rt2x00_is_usb(rt2x00dev), where this one is
> set unconditionally. Not sure if this change has side effects.

Default HW setting of WP_DMA_BURTS_SIZE is 2, hence patch does not
change behaviour on PCI devices. However I looked at RT3290 and
RT5592 PCI vendor drivers and there this value is initialized to 3.
So I think we can remove is_usb condition in rt2800_init_registers().

Stanislaw