On 26/09/2026 06:40, Dmitry Torokhov wrote:
Hi David,
On Wed, Sep 23, 2026 at 03:27:06PM +0200, David Heidelberg via B4 Relay wrote:
From: David Heidelberg <[email protected]>
System suspend powers the controller off and resume powers it back on,
but the resume path enables the interrupt before s6sy761_power_on()
checks the boot. The firmware raises its boot-complete event on the
interrupt line, the threaded handler consumes it, s6sy761_power_on()
then reads an empty event and resume fails with -ENODEV, skipping the
touch function setup:
s6sy761 2-0048: PM: dpm_run_callback(): s6sy761_resume [s6sy761] returns -19
Power the chip on first and only then unmask the interrupt. Once resume
completes the boot handshake the chip comes back with sensing off, as
at probe where input_open() turns it on, so the touchscreen stays dead
after resume. Send SENSE_ON again when the input device is open.
Tested on a Pixel 3 XL over several s2idle cycles: resume succeeds and
the touch function and sense status match the pre-suspend state.
Assisted-by: LLM
Cc: [email protected]
Fixes: 0145a7141e59 ("Input: add support for the Samsung S6SY761 touchscreen")
Signed-off-by: David Heidelberg <[email protected]>
---
drivers/input/touchscreen/s6sy761.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/input/touchscreen/s6sy761.c
b/drivers/input/touchscreen/s6sy761.c
index 0f24a9b730635..c52c45a7d1029 100644
--- a/drivers/input/touchscreen/s6sy761.c
+++ b/drivers/input/touchscreen/s6sy761.c
@@ -495,20 +495,29 @@ static int s6sy761_suspend(struct device *dev)
s6sy761_power_off(sdata);
return 0;
}
static int s6sy761_resume(struct device *dev)
{
struct s6sy761_data *sdata = dev_get_drvdata(dev);
+ int err;
+ err = s6sy761_power_on(sdata);
enable_irq(sdata->client->irq);
Why are we enabling the interrupt even if power on failed?
originally I moved the enable_irq after condition, but LLM kept convincing me
it's wrong:
enable_irq() still runs when power-on fails. That is correct, because the next
suspend or unbind calls disable_irq() again through s6sy761_power_off(), and the
two calls must stay paired.
In case of failure the power_off will be run anyway, thus it make sense to me.
+ if (err)
+ return err;
- return s6sy761_power_on(sdata);
+ guard(mutex)(&sdata->input->mutex);
+
+ if (!input_device_enabled(sdata->input))
+ return 0;
+
+ return i2c_smbus_write_byte(sdata->client, S6SY761_SENSE_ON);
Explicit return err/return 0 please - there are multiple failure points
in this function.
Sure, I'll send next version making the explicit return.
David
Thanks.
