This is a note to let you know that I've just added the patch titled sc16is7xx: Defer probe if device read fails to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sc16is7xx-defer-probe-if-device-read-fails.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 158e800e0fde91014812f5cdfb92ce812e3a33b4 Mon Sep 17 00:00:00 2001 From: Annaliese McDermond <nh6z@xxxxxxxx> Date: Mon, 29 Mar 2021 20:10:49 +0000 Subject: sc16is7xx: Defer probe if device read fails From: Annaliese McDermond <nh6z@xxxxxxxx> commit 158e800e0fde91014812f5cdfb92ce812e3a33b4 upstream. A test was added to the probe function to ensure the device was actually connected and working before successfully completing a probe. If the device was actually there, but the I2C bus was not ready yet for whatever reason, the probe fails permanently. Change the probe so that we defer the probe on a regmap read failure so that we try the probe again when the dependent drivers are potentially loaded. This should not affect the case where the device truly isn't present because the probe will never successfully complete. Fixes: 2aa916e67db3 ("sc16is7xx: Read the LSR register for basic device presence check") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Annaliese McDermond <nh6z@xxxxxxxx> Link: https://lore.kernel.org/r/010101787f9c3fd8-c1815c00-2d6b-4c85-a96a-a13e68597fda-000000@xxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sc16is7xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1196,7 +1196,7 @@ static int sc16is7xx_probe(struct device ret = regmap_read(regmap, SC16IS7XX_LSR_REG << SC16IS7XX_REG_SHIFT, &val); if (ret < 0) - return ret; + return -EPROBE_DEFER; /* Alloc port structure */ s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL); Patches currently in stable-queue which might be from nh6z@xxxxxxxx are queue-5.12/sc16is7xx-defer-probe-if-device-read-fails.patch queue-5.12/asoc-tlv320aic32x4-register-clocks-before-registering-component.patch queue-5.12/asoc-tlv320aic32x4-increase-maximum-register-in-regmap.patch