6.6-stable review patch. If anyone has any objections, please let me know.
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From: Wayne Chang waynec@nvidia.com
commit 59820fde001500c167342257650541280c622b73 upstream.
We identified a bug where the ST_RC bit in the status register was not being acknowledged after clearing the CTRL_RUN bit in the control register. This could lead to unexpected behavior in the USB gadget drivers.
This patch resolves the issue by adding the necessary code to explicitly acknowledge ST_RC after clearing CTRL_RUN based on the programming sequence, ensuring proper state transition.
Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller") Cc: stable stable@kernel.org Signed-off-by: Wayne Chang waynec@nvidia.com Link: https://lore.kernel.org/r/20250418081228.1194779-1-waynec@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/udc/tegra-xudc.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/usb/gadget/udc/tegra-xudc.c +++ b/drivers/usb/gadget/udc/tegra-xudc.c @@ -1749,6 +1749,10 @@ static int __tegra_xudc_ep_disable(struc val = xudc_readl(xudc, CTRL); val &= ~CTRL_RUN; xudc_writel(xudc, val, CTRL); + + val = xudc_readl(xudc, ST); + if (val & ST_RC) + xudc_writel(xudc, ST_RC, ST); }
dev_info(xudc->dev, "ep %u disabled\n", ep->index);