Re: FAILED: patch "[PATCH] serial: 8250_omap: Fix Errata i2310 with RX FIFO level check" failed to apply to 5.15-stable tree

["Kumar, Udit" <u-kumar1@ti.com>]

Hello Greg

On 7/3/2024 7:41 PM, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 5.15-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
>
> To reproduce the conflict and resubmit, you may use the following commands:
>
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
> git checkout FETCH_HEAD
> git cherry-pick -x c128a1b0523b685c8856ddc0ac0e1caef1fdeee5
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024070338-skid-sauna-cd1d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
>
> Possible dependencies:


This patch has dependency on 
https://lore.kernel.org/all/20240703102925.298849298@linuxfoundation.org/ 
Which is already queued for 5.15.


>
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
>  From c128a1b0523b685c8856ddc0ac0e1caef1fdeee5 Mon Sep 17 00:00:00 2001
> From: Udit Kumar <u-kumar1@ti.com>
> Date: Tue, 25 Jun 2024 21:37:25 +0530
> Subject: [PATCH] serial: 8250_omap: Fix Errata i2310 with RX FIFO level check
>
> Errata i2310[0] says, Erroneous timeout can be triggered,
> if this Erroneous interrupt is not cleared then it may leads
> to storm of interrupts.
>
> Commit 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
> which added the workaround but missed ensuring RX FIFO is really empty
> before applying the errata workaround as recommended in the errata text.
> Fix this by adding back check for UART_OMAP_RX_LVL to be 0 for
> workaround to take effect.
>
> [0] https://www.ti.com/lit/pdf/sprz536 page 23
>
> Fixes: 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
> Cc: stable@vger.kernel.org
> Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
> Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/
> Signed-off-by: Udit Kumar <u-kumar1@ti.com>
> Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index ddac0a13cf84..1af9aed99c65 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -672,7 +672,8 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
>   	 * https://www.ti.com/lit/pdf/sprz536
>   	 */
>   	if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
> -		(iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
> +	    (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
> +	    serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
>   		unsigned char efr2, timeout_h, timeout_l;
>   
>   		efr2 = serial_in(up, UART_OMAP_EFR2);
>