On 10.11.2024 8:15 PM, Krishna Kurapati wrote: > > > On 11/9/2024 2:22 AM, Konrad Dybcio wrote: >> On 7.11.2024 8:36 AM, Krishna Kurapati wrote: >>> Enabling U1 and U2 power-saving states can lead to stability and >>> performance issues, particularly for latency-sensitive or high- >>> throughput applications. These low-power link states are intended >>> to reduce power consumption by allowing the device to enter partial >>> low-power modes during idle periods. However, they can sometimes >>> result in unexpected behavior. Over the years, some of the issues >>> seen are as follows: >>> >>> 1. In device mode of operation, when UVC is active, enabling U1/U2 >>> is sometimes causing packets drops due to delay in entry/exit of >>> intermittent low power states. These packet drops are often reflected >>> as Missed Isochronous transfers as the controller was not able to >>> send the packet in that microframe interval and hence glitches are >>> seen on the final transmitted video output. >>> >>> 2. On QCS6490-Rb3Gen2 Vision kit, ADB connection is heavily unstable >>> when U1/U2 is enabled. Often when link enters U2, there is a re- >>> enumeration seen and device is unusable for many use cases. >> >> Would be nice to enable it on there too, then ;) >> >> Generally per-file commits are preferred to make potential reverts >> easier down the road >> > > Hi Konrad, > > I agree with you. After the SoB and the "---", I added a paragraph mentioning that if this RFC patch looks fine, I will send a series and make this change for all SM and QCS targets. > > Let me know if the above commit text makes sense. Although I don't have all the debug details, I didn't want others in the community face the issues we faced and hence the patch. lgtm Konrad
