On 06/02/2014 11:03, Gregory CLEMENT wrote: > Hi, > > I write this email mainly to let you know that there are some issues > on i2c on the Armada XP (rev A0 and B0) based boards. > > What we observed was that if the i2c driver try to access an address > where the device is absent, then the bus is locked. After the timeout > the driver give up, but if we have a lot of i2c client registered, > then the kernel spend a lot of time trying to scan all the > addresses. It is noticeable when using the multiv7_defconfig where > many i2c clients are registered, whereas with mvebu_defconfig we have > fewer i2c clients, and most of them are present on the boards. > > Here is an extract of what you can see during a boot: > > [ 4.127648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 4.137338] rtc-s35390a 1-0030: rtc core: registered rtc-s35390a as rtc0 > [ 6.137649] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 8.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 10.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 12.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 14.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 16.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 18.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 20.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 22.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 24.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 26.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 28.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 30.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 32.137649] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 34.137648] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 36.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 38.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 40.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 42.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 44.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 46.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 48.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 50.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 52.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 54.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 56.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 58.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 60.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 62.137648] i2c i2c-1: mv64xxx: I2C bus locked, block: 1, time_left: 0 > [ 62.144403] sdhci: Secure Digital Host Controller Interface driver > > Then the kernel continue to boot. and except this very annoying delay, > everything else is working on i2c. > > If anyone have an idea of the cause of this issue, I would be glad to > have any input. > > I continue to investigate it, and for the record v3.12 was not > affected but v3.13 was. So now I am going to bisect. Hi all, I wanted to let you know that I have just found a fix for this issue. Gregory -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- 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
