Hi Dan,

On 04/07/2016 03:41 AM, Dan Carpenter wrote:

Hello Yakir Yang,

The patch 7b4b7a8db439: "drm: bridge: analogix/dp: Fix the possible dead lock in bridge disable time" from Feb 15, 2016, leads to the following static checker warning:

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c:875 analogix_dp_irq_thread() warn: bitwise AND condition is false here

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c 869 static irqreturn_t analogix_dp_irq_thread(int irq, void *arg) 870 { 871 struct analogix_dp_device *dp = arg; 872 enum dp_irq_type irq_type; 873 874 irq_type = analogix_dp_get_irq_type(dp); 875 if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN || ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This is never true. Maybe test_bit() for these?

Ah, yep, it's an error here. The enum value of DP_IRQ_TYPE_HP_CABLE_IN is zero, so even if analogix_dp_get_irq_type return the CABLE_IN event, driver could not send the drm hpd event rightly.

Good catch, would need to assign the new enum value, like

enum dp_irq_type { - DP_IRQ_TYPE_HP_CABLE_IN, - DP_IRQ_TYPE_HP_CABLE_OUT, - DP_IRQ_TYPE_HP_CHANGE, - DP_IRQ_TYPE_UNKNOWN, + DP_IRQ_TYPE_HP_CABLE_IN = BIT(0), + DP_IRQ_TYPE_HP_CABLE_OUT = BIT(1), + DP_IRQ_TYPE_HP_CHANGE = BIT(2), + DP_IRQ_TYPE_UNKNOWN = BIT(3), };

Thanks for pointing out, would send patch to fix that soon.

- Yakir

876              irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) {
877                  dev_dbg(dp->dev, "Detected cable status changed!\n");
878                  if (dp->drm_dev)
879                          drm_helper_hpd_irq_event(dp->drm_dev);
880          }
881
882          if (irq_type != DP_IRQ_TYPE_UNKNOWN) {
883                  analogix_dp_clear_hotplug_interrupts(dp);
884                  analogix_dp_unmute_hpd_interrupt(dp);
885          }
886
887          return IRQ_HANDLED;
888  }

regards, dan carpenter