Hi Eddie,
On 3/29/2019 1:08 PM, Eddie James wrote:
On 3/28/19 4:25 PM, Jae Hyun Yoo wrote:
To prevent this issue, this commit adds spinlock protection and clock
status checking logic into the Aspeed video engine driver.
Thanks Jae. Do you have a reliable way to reproduce this? Haven't seen
it myself.
It could be observed when user space releases a video engine dev entry
handle while video mode is changing. You could reproduce it by repeating
reload of KVM web page just after trigger a host reset. It rarely
happens.
+ bool is_video_on;
This can probably be a flag, like VIDEO_CLOCKS_ON, not a new boolean.
Okay, I'll add the bit field into video->flags.
+ aspeed_video_reset(video);
I'm working on a patch to remove the use of the reset line too.
Right, since clk-aspeed module can trigger a reset while enabling the
vclk or eclk, it could be removed later, but this patch is not for that.
+ spin_lock(&video->lock);
Is there a reason you're locking extra code? Why not put the lock in the
aspeed_video_on/off functions?
aspeed_video_on() and aspeed_video_off() can be called from driver
context and from interrupt context so some video enable/disable
relating code also need to be serialized.
Will submit v2 soon after replacing the boolean variable with
VIDEO_CLOCKS_ON flag.
Thanks,
Jae
