[RFC] How working MMC_BUS_WIDTH_TEST??

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi..

I found the MMC_CAP_BUS_WIDTH_TEST...
In mailing, I read the related patches..
but i didn't fully understand...

/*
 * If controller can't handle bus width test,
 * compare ext_csd previously read in 1 bit mode
 * against ext_csd at new bus width
 */
if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
	err = mmc_compare_ext_csds(card,
		ext_csd,
		bus_width);
else
	err = mmc_bus_test(card, bus_width);
if (!err)
	break;

And i tested suspend/resume..it's failed..
If i didn't set MMC_CAP_BUS_WIDTH_TEST, always return -EINVAL..
(using SDHCI controller, card is eMMC4.41)

Didn't compare ext_csd's value..

So i want to know how use MMC_CAP_BUS_WIDTH_TEST..

Thanks,
Jaehoon Chung