Venkat, Were you seeing endless printing of that message? On Moorestown or Medfield?
Last time, Yakui Zhao told me he saw endless printing of the this message on his MRST CDK, and removing the "earlyprintk=mrst" solved his problem. If you randomly see that message, it's ok, otherwise we don't need that warning at all. Btw, the DW SPI controller supports 3 working modes: PIO, DMA and interrupt driven, current max3110 use the PIO mode, which will check status register after every IO read/write. Migrating to interrupt mode will save you from seeing that message, but due to the poor interrupt latency from MRST non-OS side, I don't really recommend that. - Feng > -----Original Message----- > From: Jayaraman, Venkat > Sent: Saturday, February 19, 2011 8:49 AM > To: Tang, Feng; [email protected]; [email protected] > Subject: RE: [Meego-kernel] Question on Designware SPI Controller Driver > > Feng, > I see the message even if I remove "earlyprintk=mrst" from the cmdline. > Why could this be happening? Do I have to disable MRST_EARLY_PRINT from the > config? > > Venkat > > -----Original Message----- > From: Tang, Feng > Sent: Friday, February 18, 2011 1:37 AM > To: [email protected]; Jayaraman, Venkat; [email protected] > Subject: RE: [Meego-kernel] Question on Designware SPI Controller Driver > > Yes, it should affect all other devices connecting to the SPI0 controller, > when > early console is printing sth out while the controller is accessed by other > devices through spi core, the early console will be disabled after the ttyS0 > gets the control > > > -----Original Message----- > > From: [email protected] [mailto:[email protected]] > > Sent: Friday, February 18, 2011 5:15 PM > > To: Tang, Feng; Jayaraman, Venkat; [email protected] > > Subject: RE: [Meego-kernel] Question on Designware SPI Controller Driver > > > > Hello, > > > > This problem also confuse me long time ago. > > I change module_init(serial_m3110_init) to be > > late_initcall(serial_m3110_init) to avoid this problem. > > > > May I ask that if the root cause is conflict between the MRST earlyprintk > console > > and the real spi max3110 console, is there possible also conflict other SPI > > device? > > > > Thank you. > > > > Sincerely, > > Major Lee > > > > > > > > > > > -----Original Message----- > > > From: [email protected] > > > [mailto:[email protected]] On Behalf Of Tang, Feng > > > Sent: Friday, February 18, 2011 4:24 PM > > > To: Jayaraman, Venkat; [email protected] > > > Subject: Re: [Meego-kernel] Question on Designware SPI > > > Controller Driver > > > > > > Hi Venkat, > > > > > > I've heard several reports about the annoying message. > > > > > > The reason for it should be the conflict between the MRST > > > earlyprintk console (earlyprintk=mrst in cmdline) and the > > > real spi max3110 console aka ttyS0, and actually the 2 > > > consoles use the same hardware. > > > > > > I developed that early console mainly for MRST/MDF power > > > on use, which is to debug the early kernel boot by hacky > > > direct operating the DW SPI0 controller, long before the > > > spi driver subsystem get inited which I developed for the > > > MRST power on So when the spi subsystem is up, there is > > > conflict between them, other spi devices connected to > > > SPI0 including max3110 itself will access the SPI0 controller > > > by apis from spi core, while the earlyprintk still directly > > > access controller, so likely the message will be triggered out. > > > > > > And in current phase, the earlyprintk should be disabled for > > > normal stable kernels, and I suggest to remove the > > > "earlyprintk=mrst" from cmdline for Meego kernel. Another way > > > is to downgrade the error message to a dev_dbg(). > > > > > > Thanks, > > > Feng > > > ________________________________________ > > > From: [email protected] > > > [mailto:[email protected]] On Behalf Of > > > Jayaraman, Venkat > > > Sent: Friday, February 18, 2011 3:03 PM > > > To: [email protected] > > > Subject: [Meego-kernel] Question on Designware SPI Controller Driver > > > > > > Hi, > > > I consistently see the following message > > > being printed from the Designware SPI controller driver > > > (dw_spi.c) during the booting phase on Medfield platform. > > > > > > "Status keeps busy for 5000us after a read/write" > > > > > > Seems like a "write" inside the interrupt > > > handler is causing this. Any idea why this happens? > > > > > > Thanks > > > Venkat > > > _______________________________________________ > > > MeeGo-kernel mailing list > > > [email protected] > > > http://lists.meego.com/listinfo/meego-kernel > > > _______________________________________________ MeeGo-kernel mailing list [email protected] http://lists.meego.com/listinfo/meego-kernel
