Shubro, As Grygorii pointed out we had a generic issue of arm getting interrupted for i2c accesses outside it (IPU in case of omap4/omap5) and to avoid that we would enable/disable mpu level interrupts only when required from i2c-omap driver. Regards Huzefa -----Original Message----- From: Datta, Shubhrajyoti Sent: Friday, October 12, 2012 6:33 AM To: Strashko, Grygorii Cc: Kevin Hilman; Kalle Jokiniemi; linux-i2c@xxxxxxxxxxxxxxx; w.sang@xxxxxxxxxxxxxx; ben-linux@xxxxxxxxx; tony@xxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; Kankroliwala, Huzefa Subject: Re: [PATCH v3] ARM: OMAP: i2c: fix interrupt flood during resume On Friday 12 October 2012 03:48 PM, Strashko, Grygorii wrote: > Hi All, > > Sorry, for the late reply. > + CC Huzefa Kankroliwala - who is I2C driver owner on Android Kernel 3.4. > > Regarding this patch hmm I had similar ideas however my idea was to pacify the arm interrupts when the ip is used by another processor.(something my hw spin patch missed) Any-ways will wait for Huzefa to comment. > - from my point of view, it fixes corner case and not an issue in general. > Let take a look on resume sequence: > - platform resume > - syscore resume > - resume_noirq > - enable IRQs - resume_device_irqs() > |- at this point IRQ handler will be invoked if IRQ state is IRQS_PENDING. > |- so, the I2C device IRQ handler may be called at time when I2C adapter IRQ is still disabled and, as result, the I2C device IRQ-handler may fail. (I2C device and I2C adapter may use different physical IRQ lines) > - resume_late > |- enable I2C bus IRQ > > Possibly, the better way is to enable/disable I2C bus IRQ when needed - in our case in omap_i2c_xfer(). > We use such approach in Android kernel 3.4 > (http://git.omapzoom.org/?p=kernel/omap.git;a=commitdiff;h=1445a4d3b587c164bd30d108b61760aaaa07365e) > > Grygorii > ______________________ -- 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
