On 30 August 2016 at 22:51, Simon Horman <horms@xxxxxxxxxxxx> wrote: > On Mon, Aug 29, 2016 at 04:05:55PM +0200, Ulf Hansson wrote: >> On 29 August 2016 at 14:05, Simon Horman <horms@xxxxxxxxxxxx> wrote: >> > On Fri, Aug 26, 2016 at 10:01:35AM +0200, Ulf Hansson wrote: >> >> On 25 August 2016 at 14:04, Simon Horman <horms@xxxxxxxxxxxx> wrote: >> >> > On Tue, Aug 23, 2016 at 05:02:56PM +0200, Ulf Hansson wrote: >> > >> > ... > > ... > >> > @@ -1271,6 +1278,7 @@ int tmio_mmc_host_runtime_suspend(struct device *dev) >> > >> > mmc_retune_timer_stop(host->mmc); >> > mmc_retune_needed(host->mmc); >> > + host->use_saved_taps = true; >> >> I don't think you should trigger a re-tune here at all. Moreover you >> don't need to keep track of whether you have valid tap values by using >> the ->use_saved_taps variable, the mmc core deals with this for you. >> >> Instead, you should restore the tap values by invoking >> host->select_tuning() from the ->runtime_resume() callback, although >> only when host->mmc->can_retune == 1. We should probably add a helper >> function in the mmc core for this check, instead of accessing >> "can_retune" directly. > > Thanks, I was wondering what the best way to handle this is. > > I tried your suggestion above but it seems that host->mmc->can_retune is > zero when ->runtime_resume() is called because of the following call paths: > > a) _mmc_sd_suspend() > -> mmc_power_off() > -> mmc_set_initial_state() > -> mmc_retune_disable > and > b) mmc_sd_runtime_resume() > -> mmc_power_up > -> mmc_set_initial_state() > -> mmc_retune_disable > >> > tmio_mmc_disable_mmc_irqs(host, TMIO_MASK_ALL); This is exactly what shall happen :-) If the mmc core suspends the card, it means it will also re-initialize the card when resuming it. In that way the regular tuning sequence will take place as a part of re-initialization of the card, so you definitely must not restore tap values in these case. That is why you should be using the can_retune to know when to restore the values. > > > I plan to repost this patchset without the tap restoration code. > This is because I have a number of changes locally, in particular > to address other parts of your review, and I would like > them to see the light of day. > > I will mark the tap restoration as a TODO item which we can address > before merging the code in question. It shouldn't be that hard to implement this, so I rather see that we get this right from the beginning. As matter of fact it probably requires less code than you had in your initial approach, especially since I don't think you need to deal with anything tuning related in the ->runtime_suspend() callback, but only in ->runtime_resume(). Kind regards Uffe
