[PATCH 1/5] phy: cpcap-usb: Prevent line glitches from triggering sysrq
Ivaylo Dimitrov <[email protected]> Sat, 4 Jul 2026 10:38:39 +0300
| Newsgroups | org.kernel.vger.linux-omap,org.infradead.lists.linux-phy,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-gpio,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
From: Tony Lindgren <[email protected]> We can get random sysrq events on switching from USB to debug serial port mode unless is temporarily disable sysrq for the mode changes. Signed-off-by: Tony Lindgren <[email protected]> --- drivers/phy/motorola/phy-cpcap-usb.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/phy/motorola/phy-cpcap-usb.c b/drivers/phy/motorola/phy-cpcap-usb.c index 7cb020dd3423..c6cc8fce6940 100644 --- a/drivers/phy/motorola/phy-cpcap-usb.c +++ b/drivers/phy/motorola/phy-cpcap-usb.c @@ -20,6 +20,7 @@ #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/slab.h> +#include <linux/sysrq.h> #include <linux/gpio/consumer.h> #include <linux/mfd/motorola-cpcap.h> @@ -413,7 +414,12 @@ static int cpcap_usb_gpio_set_mode(struct cpcap_phy_ddata *ddata, static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata) { - int error; + int sysrq, error; + + /* Disable sysrq to prevent random sysrq events on line glitches */ + sysrq = sysrq_mask(); + if (sysrq & 1) + sysrq_toggle_support(sysrq & ~1); /* Disable lines to prevent glitches from waking up mdm6600 */ error = cpcap_usb_gpio_set_mode(ddata, CPCAP_UNKNOWN_DISABLED); @@ -448,6 +454,9 @@ static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata) if (error) goto out_err; + if (sysrq & 1) + sysrq_toggle_support(sysrq); + return 0; out_err: -- 2.25.1