Re: [4.1] rtlwifi: Remove the clear interrupt routine from all drivers

[Kalle Valo <kvalo@codeaurora.org>]

> From: Vincent Fann <vincent_fann@realtek.com>
> 
> Several of these drivers have there TX randomly blocked for 3~5 seconds while
> measuring tx throughput (iperf). The root couse happens in rtl_pci_flush().
> The function uses a while-loop to wait for TX queue length to decrease to 0.
> The TX queue length counts the number of packets that are queued in the driver.
> The driver relys on the TX OK interrupt to return skb and reduce TX queue length.
> 
> The interrupt subroutine disables interupts, reads the interrupt registers, and
> then clears the registers in the beginning of _rtl_pci_interrupt(). After all
> interupts process are finished, the driver invokes enable_interrupt() to enable
> interupts. This behavior is normal for an interrupt subroutine.
> 
> But enable_interrupt() invokes clear_interrupt() again. This unexpected interrupt
> clearing may cleari me fresh TX OK interrupts. These missing interrupts cause TX
> queue length to never reduce to 0i, which causes rtl_pci_flush() to be stuck in
> unterminated while-loop.
> 
> This patch removes clear_interrupt() in enable_interrupt() to avoid this behavior.
> 
> Signed-off-by: Vincent Fann <vincent_fann@realtek.com>
> Signed-off-by: Shao Fu <shaofu@realtek.com>
> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
> Cc: Stable <stable@vger.kernel.org> [3.18+]

Thanks, applied to wireless-drivers-next.git.

Kalle Valo