12.08.2020 07:03, Wright Feng пишет:
...
> Hi Dmitry,
>
> The last time the drivers I used is v5.4 and I was not able to see low
> throughput issue as you saw.
> At this time, I changed the base to tag wt-2020-0727 and I am able to
> reproduce the issue as you did.
> TX throughput with wt-2020-07-27 FMAC is 190 Kbits/sec
>
>
> The root cause should be that tx_max and tx_seq are circle positive
> numbers, it should not use ">" to check if it still exists available TX
> credit.
> With the solution below, I am able to get the normal throughput.
> TX throughput with wt-2020-07-27+patch FMAC is 40.0 Mbits/sec
>
> Regarding another case about 40Mbit/s, I am using 4329b0(4329/2) chip to
> verify the throughput because we are not able to find 4329b1(4329/3)
> which is very old product around 10 years ago.
> The firmware I am using is the same version but the build is for 4329b0.
> (private internal build - 4.220.48). My host platform is x86_64 with 4
> cores on Linux kernel 4.12. I will try your NVRAM when I have time to
> see if I can find anything.
>
> ---
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> index e8712ad..50c8107 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> @@ -664,9 +664,14 @@ static void pkt_align(struct sk_buff *p, int len,
> int align)
> /* To check if there's window offered */
> static bool data_ok(struct brcmf_sdio *bus)
> {
> - /* Reserve TXCTL_CREDITS credits for txctl */
> - return (bus->tx_max - bus->tx_seq) > TXCTL_CREDITS &&
> - ((bus->tx_max - bus->tx_seq) & 0x80) == 0;
> + u8 tx_rsv = 0;
> +
> + /* Reserve TXCTL_CREDITS credits for txctl when it is ready to send */
> + if (bus->ctrl_frame_stat)
> + tx_rsv = TXCTL_CREDITS;
> +
> + return (bus->tx_max - bus->tx_seq - tx_rsv) != 0 &&
> + ((bus->tx_max - bus->tx_seq - tx_rsv) & 0x80) == 0;
> }
>
> /* To check if there's window offered */
> ---
Wright, thank you very much for the patch! It fixes the problem!
Tested-by: Dmitry Osipenko <digetx@xxxxxxxxx>
The 4329/3 is indeed an older chip, but it's also an "old" device (Acer
A500 tablet from 2011/12) that I'm using. Upstream v5.9 kernel just got
support for the A500. There are quite a lot of other older devices with
4329/3 in a wild that are still very usable if user can wipe off ancient
Android and put a modern Linux distro on them. Today that A500 tablet is
still rocking hard running a modern upstream kernel, opensource drivers
and KDE Plasma 5. The 15Mbit is a good enough speed for a lot of things,
but of course 40Mbit will be better. Would be great if you could try to
help with improving the speed :) Please feel free to contact me at any
time if you'll have patches to try!
