From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren@wwwdotorg.org>
Date: Wed, 03 Sep 2014 09:48:06 -0600
Subject: [U-Boot] [PATCH 2/2] mmc: restore capacity when switching to
 partition 0
In-Reply-To: <1409700683-25393-3-git-send-email-pab@pabigot.com>
References: <1409700683-25393-1-git-send-email-pab@pabigot.com>
	<1409700683-25393-3-git-send-email-pab@pabigot.com>
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On 09/02/2014 05:31 PM, Peter A. Bigot wrote:
> The capacity and lba for an MMC device with part_num 0 reflects the
> whole device.  When mmc_switch_part() successfully switches to a
> partition, the capacity is changed to that partition.  As partition 0
> does not physically exist, attempts to switch back to the whole device
> will indicate an error, but the capacity setting for the whole device
> must still be restored to match the partition.

> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c

> @@ -594,10 +594,15 @@ int mmc_switch_part(int dev_num, unsigned int part_num)
>   	ret = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_PART_CONF,
>   			 (mmc->part_config & ~PART_ACCESS_MASK)
>   			 | (part_num & PART_ACCESS_MASK));
> -	if (ret)
> -		return ret;
>
> -	return mmc_set_capacity(mmc, part_num);
> +	/*
> +	 * Set the capacity if the switch succeeded or was intended
> +	 * to return to representing the raw device.
> +	 */
> +	if ((ret == 0) || ((ret == -ENODEV) && (part_num == 0)))
> +		ret = mmc_set_capacity(mmc, part_num);
> +
> +	return ret;
>   }

I think this wouldn't be needed without patch 1/2, since without that 
patch, no partition switching should ever happen if HW partitions don't 
exist, and hence this patch shouldn't be required.