2024-03-21 14:19:54

by Maxim Levitsky

[permalink] [raw]
Subject: [PATCH] i2c: i801: Fix a refactoring that broke a touchpad on Lenovo P1

Commit 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")
introduced a slight functional change: the status variable is now
overwritten with the length of an SMBUS tranasaction,
even in case of success.

This breaks the touchpad on at least my Lenovo P1:

rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
rmi4_physical rmi4-00: RMI initial reset failed! Continuing in spite of this.
rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
rmi4_physical rmi4-00: IRQ counting failed with code -6.

Fixes: 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")

Signed-off-by: Maxim Levitsky <[email protected]>
---
drivers/i2c/busses/i2c-i801.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index a6861660cb8c..79870dd7a014 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -536,11 +536,12 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,

if (read_write == I2C_SMBUS_READ ||
command == I2C_SMBUS_BLOCK_PROC_CALL) {
- status = i801_get_block_len(priv);
- if (status < 0)
+ len = i801_get_block_len(priv);
+ if (len < 0) {
+ status = len;
goto out;
+ }

- len = status;
data->block[0] = len;
inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */
for (i = 0; i < len; i++)
--
2.40.1



2024-03-21 16:11:33

by Heiner Kallweit

[permalink] [raw]
Subject: Re: [PATCH] i2c: i801: Fix a refactoring that broke a touchpad on Lenovo P1

On 21.03.2024 15:19, Maxim Levitsky wrote:
> Commit 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")
> introduced a slight functional change: the status variable is now
> overwritten with the length of an SMBUS tranasaction,
> even in case of success.
>
> This breaks the touchpad on at least my Lenovo P1:
>
> rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
> rmi4_physical rmi4-00: RMI initial reset failed! Continuing in spite of this.
> rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
> rmi4_physical rmi4-00: IRQ counting failed with code -6.
>
> Fixes: 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")
>
> Signed-off-by: Maxim Levitsky <[email protected]>
> ---
> drivers/i2c/busses/i2c-i801.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index a6861660cb8c..79870dd7a014 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -536,11 +536,12 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,
>
> if (read_write == I2C_SMBUS_READ ||
> command == I2C_SMBUS_BLOCK_PROC_CALL) {
> - status = i801_get_block_len(priv);
> - if (status < 0)
> + len = i801_get_block_len(priv);
> + if (len < 0) {
> + status = len;
> goto out;
> + }
>
> - len = status;
> data->block[0] = len;
> inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */
> for (i = 0; i < len; i++)

Indeed, my bad.

Reviewed-by: Heiner Kallweit <[email protected]>


2024-03-21 20:42:55

by Andi Shyti

[permalink] [raw]
Subject: Re: [PATCH] i2c: i801: Fix a refactoring that broke a touchpad on Lenovo P1

Hi Maxim,

On Thu, Mar 21, 2024 at 10:19:19AM -0400, Maxim Levitsky wrote:
> Commit 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")
> introduced a slight functional change: the status variable is now
> overwritten with the length of an SMBUS tranasaction,
> even in case of success.
>
> This breaks the touchpad on at least my Lenovo P1:
>
> rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
> rmi4_physical rmi4-00: RMI initial reset failed! Continuing in spite of this.
> rmi4_physical rmi4-00: Read PDT entry at 0x00e9 failed, code: -6.
> rmi4_physical rmi4-00: IRQ counting failed with code -6.
>
> Fixes: 857cc04cdf50 ("i2c: i801: Add helper i801_get_block_len")
>

next time please drop this blank line here.

Applied to i2c/i2c-host-fixes on

git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git

Thank you,
Andi

Patches applied
===============
[1/1] i2c: i801: Fix a refactoring that broke a touchpad on Lenovo P1
commit: a5894bc48f64caa86dbea1744d067c925303c5fc