On Tue, Feb 12, 2019 at 02:24:47PM +0100, LorenzoBianconilorenzo@xxxxxxxxxx wrote:
> From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
>
> Use linear fragment and not a single usb scatter-gather buffer in mt76u
> {tx,rx} datapath if the usb controller has sg data length constraints.
> Moreover add disable_usb_sg module parameter in order to explicitly
> disable scatter-gather. SG I/O is not supported by all host drivers and
> some users have reported sg issues on AMD IOMMU.
Again. This is not right approach. SG issues should be fixed
not workarounded.
> This series has been tested on AMD IOMMU cpus/motherboards and on rpi3+
> - rebased on top of 'fix multiple issues in mt76u error path'
> https://patchwork.kernel.org/cover/10804919/
>
> Lorenzo Bianconi (4):
> mt76: usb: move mt76u_check_sg in usb.c
> mt76: usb: do not use sg buffers for mcu messages
> mt76: usb: use a linear buffer for tx/rx datapath if sg is not
> supported
> mt76: usb: introduce disable_usb_sg parameter
>
> drivers/net/wireless/mediatek/mt76/mt76.h | 14 +-
> .../net/wireless/mediatek/mt76/mt76x0/usb.c | 2 +-
> .../wireless/mediatek/mt76/mt76x02_usb_mcu.c | 3 +-
> .../wireless/mediatek/mt76/mt76x2/usb_init.c | 2 +-
> drivers/net/wireless/mediatek/mt76/usb.c | 133 +++++++++++++-----
> drivers/net/wireless/mediatek/mt76/usb_mcu.c | 5 +-
> 6 files changed, 105 insertions(+), 54 deletions(-)
I really think my approach is simpler. Diffstat from my proposed patch is:
drivers/net/wireless/mediatek/mt76/mt76.h | 1 +
drivers/net/wireless/mediatek/mt76/usb.c | 55 ++++++++++++++---------
2 files changed, 36 insertions(+), 20 deletions(-)
Also this fix bug(s), presumably regression for mt76x0, should be
backported.
Stanislaw
