On 4/18/23 6:31 PM, Johan Hovold wrote:
On Tue, Apr 18, 2023 at 05:48:35PM +0530, Udipto Goswami wrote:
First, the subject of this patch looks wrong.
When the dwc3 device is runtime suspended, various required clocks would
get disabled and it is not guaranteed that access to any registers would
work. Depending on the SoC glue, a register read could be as benign as
returning 0 or be fatal enough to hang the system.
In order to prevent such scenarios of fatal errors, make sure to resume
dwc3 then allow the function to proceed.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
I did not sign-off on this patch (and neither did Oliver I presume).
You must never add a SoB on behalf on someone else without their
permission. Please read Documentation/process/submitting-patches.rst and
make sure you understand what SoB means before sending any further
patches.
Signed-off-by: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
---
v5: Reworked the patch to resume dwc3 while accessing the registers.
Please include the full changelog for v6 (and future patches).
drivers/usb/dwc3/debugfs.c | 123 +++++++++++++++++++++++++++++++++++++
1 file changed, 123 insertions(+)
diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index e4a2560b9dc0..d622b0dfeb76 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -332,6 +332,13 @@ static int dwc3_lsp_show(struct seq_file *s, void *unused)
unsigned int current_mode;
unsigned long flags;
u32 reg;
+ int ret;
+
+ ret = pm_runtime_get_sync(dwc->dev);
+ if (!ret || ret < 0) {
This is broken as you would not print anything on success (ret == 0).
Did you test this patch at all?
+ pm_runtime_put(dwc->dev);
+ return 0;
Why do you return 'success' on errors?
Hi Johan,
I think missed this one will fix it in v6.
+ }
Johan
