RE: [PATCH] wifi: rtw88: sdio: Honor the host max_req_size in the RX path

[Ping-Ke Shih <pkshih@realtek.com>]

> -----Original Message-----
> From: Lukas F. Hartmann <lukas@mntre.com>
> Sent: Thursday, July 13, 2023 8:49 PM
> To: Ping-Ke Shih <pkshih@realtek.com>; Martin Blumenstingl <martin.blumenstingl@googlemail.com>;
> linux-wireless@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org; jernej.skrabec@gmail.com; ulf.hansson@linaro.org; kvalo@kernel.org;
> tony0620emma@gmail.com
> Subject: RE: [PATCH] wifi: rtw88: sdio: Honor the host max_req_size in the RX path
> 
> Hi,
> 
> Ping-Ke Shih <pkshih@realtek.com> writes:
> 
> > I assume your conclusion is correct for all platforms, so I add my reviewed-by.
> > But, I think it would be better that Lukas can help to test this patch on his
> > platform, and give a tested-by tag before getting this patch merged.
> 
> I have been testing this now more rigorously in my own laptop with
> Kernel 6.4.1 (from Debian experimental) and this patch applied. I first
> had issues with rtw_power_mode_change (and "firmware failed to leave lps
> state"), so I turned off power_save using iw. This made everything
> quiet, but unfortunately after about 1 hour of usage I get
> skb_over_panic again and I believe some memory corruption happens in the
> kernel, as I can do dmesg only once and then another dmesg will hang forever.
> (After WARNING: CPU: 4 PID: 0 at kernel/context_tracking.c:128
> ct_kernel_exit.constprop.0+0xa0/0xa8)
> 
> Here are the errors that lead up to this:
> http://dump.mntmn.com/rtw88-failure-1h-dmesg.txt

Hi Martin,

The dmesg shows that
"rtw_8822cs mmc2:0001:1: Failed to read 1536 byte(s) from SDIO port 0x000000d1"

Shouldn't we return an error code (with proper error handling) instead of
just break the loop? Because 'buf' content isn't usable. 

I wonder the approach of this patch is still not enough for Lukas' platform. 

Ping-Ke