On Friday 19 September 2014, Octavian Purdila wrote: > +struct dln2_gpio_pin { > + __le16 pin; > +} __packed; This does not need to be marked packed, since it is never embedded in another structure. > +struct dln2_gpio_pin_val { > + __le16 pin; > + u8 value; > +} __packed; It's enough here to mark just the 'pin' member as packed. > +static int dln2_gpio_get_pin_count(struct platform_device *pdev) > +{ > + int ret; > + __le16 count; > + int len = sizeof(count); > + > + ret = dln2_transfer(pdev, DLN2_GPIO_GET_PIN_COUNT, NULL, 0, &count, > + &len); You must not do a USB transaction on stack memory. > +static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin) > +{ > + struct dln2_gpio_pin req = { > + .pin = cpu_to_le16(pin), > + }; > + > + return dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), NULL, NULL); > +} Same here > +static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin) > +{ > + int ret; > + struct dln2_gpio_pin req = { > + .pin = cpu_to_le16(pin), > + }; > + struct dln2_gpio_pin_val rsp; And here. > +static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset, > + unsigned debounce) > +{ > + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); > + struct { > + __le32 duration; > + } __packed req = { > + .duration = cpu_to_le32(debounce), > + }; > + > + return dln2_transfer(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE, > + &req, sizeof(req), NULL, NULL); > +} Here you also have a strange __packed attribute that makes no sense for a local variable, in addition to the stack problem. I think the only correct way to handle these is to add a dynamic allocation of an entire page for the DMA, which can probably be part of the dln2_transfer function so you don't have to do it in each caller. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html