Hi Saravana, On 25/03/2020 23:56, Saravana Kannan wrote: > On Wed, Mar 25, 2020 at 2:47 PM Thomas Gleixner > <tglx@xxxxxxxxxxxxx> wrote: >> >> Saravana Kannan <saravanak@xxxxxxxxxx> writes: >>> On Tue, Mar 24, 2020 at 11:34 AM Saravana Kannan >>> <saravanak@xxxxxxxxxx> wrote: I took a closer look. So two >>> different drivers [1] [2] are saying they know how to handle >>> "arm,vexpress-sysreg" and are expecting to run at the same >>> time. That seems a bit unusual to me. I wonder if this is a >>> violation of the device-driver model because this expectation >>> would never be allowed if these device drivers were actual >>> drivers registered with driver-core. But that's a discussion >>> for another time. >>> >>> To fix this issue you are facing, this patch should work: >>> https://lore.kernel.org/lkml/20200324195302.203115-1-saravanak@xxxxxxxxxx/T/#u >> >> >>> >>> >>> > Sorry, that's not a fix. That's a crude hack. > > If device nodes are being handled by drivers without binding a > driver to struct devices, then not setting OF_POPULATED is wrong. > So the original patch sets it. There are also very valid reasons > for allowing OF_POPULATED to be cleared by a driver as discussed > here [1]. > > The approach of the original patch (setting the flag and letting > the driver sometimes clear it) is also followed by many other > frameworks like irq, clk, i2c, etc. Even ingenic-timer.c already > does it for the exact same reason. > > So, why is the vexpress fix a crude hack? > >> As this is also causing trouble on tegra30-cardhu-a04 the only >> sane solution is to revert it and start over with a proper >> solution for the vexpress problem and a root cause analysis for >> the tegra. > > If someone can tell me which of the timer drivers are relevant for > tegra30-cardhu-a04, I can help fix it. If you want to revert the > original patch first before waiting for a tegra fix, that's okay by > me. It seems the OF_POPULATED flag change spotted something wrong in different drivers and that is a good thing. Thanks for your patch for that. Without putting in question your analysis, we need to stabilize the release, can you send a revert of your patch? Let's try to figure out what is happening and fix the issues in the other drivers for the next cycle. Thanks -- Daniel -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
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