RE: [PATCH] wifi: rtw88: sdio: Fix unhandled RX request interrupt storm

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

Ping-Ke Shih wrote:
> 
> Hi Martin,
> 
> Alastair D'Silva <alastair@d-silva.org> wrote:
> > In rtw_sdio_handle_interrupt(), the HISR status register is cleared using
> > Write-1-to-Clear (W1C) semantics. However, the driver masks out the
> > REG_SDIO_HISR_RX_REQUEST bit in the local 'hisr' variable before writing
> > it back, causing a 0 to be written to that bit.
> 
> I feel this patch makes sense.
> 
> Did you remember why you clear the bit locally? Can you share vendor
> driver you referenced?
> 

I asked internal expert who said this bit will be cleared automatically
if all packets in RX buffer are received. If we clear this bit here,
the interrupt will not raise again if no newly incoming packet even
there are remaining packets in RX buffer. 

Checking rtw_sdio_rx_isr(), we can see it reads hisr for each iteration,
which this is also the evidence that the bit will be cleared automatically.

Therefore, we need to dig further why the RX buffer can't be empty
and get stuck. 

Ping-Ke