On 12/19/13 10:01, Adrian Hunter wrote:
On 19/12/13 01:00, Stephen Warren wrote:
On 12/18/2013 03:27 PM, Stephen Warren wrote:
From: Stephen Warren<swarren@xxxxxxxxxx>
In mmc_do_calc_max_discard(), if only a single erase block can be
discarded within the host controller's timeout, don't allow discard
operations at all.
Previously, the code allowed sector-at-a-time discard (rather than
erase-block-at-a-time), which was chronically slow.
Without this patch, on the NVIDIA Tegra Cardhu board, the loops result
in qty == 1, which is immediately returned. This causes discard to
operate a single sector at a time, which is chronically slow. With this
patch in place, discard operates a single erase block at a time, which
is reasonably fast.
Alternatively, is the real fix a revert of e056a1b5b67b "mmc: queue: let
host controllers specify maximum discard timeout", followed by:
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 050eb262485c..35c5b5d86c99 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1950,7 +1950,6 @@ static int mmc_do_erase(struct mmc_card *card, unsigned int from,
cmd.opcode = MMC_ERASE;
cmd.arg = arg;
cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
- cmd.cmd_timeout_ms = mmc_erase_timeout(card, arg, qty);
err = mmc_wait_for_cmd(card->host,&cmd, 0);
if (err) {
pr_err("mmc_erase: erase error %d, status %#x\n",
@@ -1962,7 +1961,7 @@ static int mmc_do_erase(struct mmc_card *card, unsigned int from,
if (mmc_host_is_spi(card->host))
goto out;
- timeout = jiffies + msecs_to_jiffies(MMC_CORE_TIMEOUT_MS);
+ timeout = jiffies + msecs_to_jiffies(mmc_erase_timeout(card, arg, qty));
do {
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_SEND_STATUS;
That certainly also seems to solve the problem on my board...
But large erases will timeout when they should have been split into smaller
chunks.
A generic solution needs to be able to explain what happens when the host
controller *does* timeout.
Please correct me, but if Data Timeout Error is disabled, then this is not
an issue for most of the host controllers.
With best wishes,
Vladimir
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