Messages in this thread | | | Date | Wed, 8 Jul 2015 08:43:04 +0200 | From | Sascha Hauer <> | Subject | Re: SDHCI: mdelay() in hot path in esdhc_pltfm_set_clock looses CAN (!) frames |
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On Wed, Jul 08, 2015 at 08:22:57AM +0200, Holger Schurig wrote: > Wow, at last some reaction. And I thought nobody cares ... > > BTW, removing CONFIG_MMC_CLKGATE helped a bit, because the pointless > clock-off-clock-on while the device is booting (or accessing multiple > sectors within a short time) isn't going to happen anymore. > > But really, a mdelay(1) in a driver ...
Look for the other mdelays in sdhci.c. There are up to a hundred of them in sdhci_reset() which is called under a spin_lock_irqsave. I remember that with the wrong type of card detection the MMC core frequently polls for a card and if none is found the sdhci core was resetted which falls into this mdelay polling loop in sdhci_reset. So if you care about realtime you better have a card inserted...
Sascha
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