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From: Jaehoon Chung <jh80.chung@samsung.com>
To: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Cc: Chris Ball <cjb@laptop.org>, Philip Rakity <prakity@marvell.com>,
	Kyungmin Park <kyungmin.park@samsung.com>
Subject: [RFC] How working MMC_BUS_WIDTH_TEST??
Date: Tue, 28 Jun 2011 19:54:27 +0900	[thread overview]
Message-ID: <4E09B2E3.20903@samsung.com> (raw)

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

             reply	other threads:[~2011-06-28 10:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-28 10:54 Jaehoon Chung [this message]
2011-06-28 19:50 ` [RFC] How working MMC_BUS_WIDTH_TEST?? Philip Rakity
2011-06-29  4:42   ` Jaehoon Chung
2011-06-29  4:46     ` Philip Rakity
2011-06-30  2:12       ` Jaehoon Chung

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