On 2 February 2015 at 16:05, Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxxx> wrote:
> On Mon, Feb 02, 2015 at 03:57:37PM +0100, Ulf Hansson wrote:
>> On 30 January 2015 at 23:27, NeilBrown <neilb@xxxxxxx> wrote:
>> > Shortly before this call is
>> >
>> > host->ios.power_mode = MMC_POWER_ON;
>> > mmc_set_ios(host);
>> >
>> > and omap_hsmmc_set_ios() contains:
>> >
>> > switch (ios->power_mode) {
>> > ....
>> > case MMC_POWER_ON:
>> > do_send_init_stream = 1;
>> > break;
>> >
>> >
>> > if (do_send_init_stream)
>> > send_init_stream(host);
>> >
>> > Which sends the "init stream" to the card.
>> > If the card is still being reset at this time, the stream may not
>> > be effective.
>> >
>> > I find that about 10%-20% of the time when I release the reset line
>> > *after* the sequence is sent, my card fails to initialised. When I
>> > release *before* the sequence is sent, it never fails.
>>
>> Okay, thanks for providing these details.
>
> The right thing to do then is to pulse the reset line at the pre-power-up
> stage.
I don't think that will work, since the card hasn't yet been powered
and will thus not respond properly to the reset.
Kind regards
Uffe
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