* Re: [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal
2013-02-28 7:29 [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal Kevin Liu
@ 2013-02-28 8:46 ` Ulf Hansson
2013-02-28 9:34 ` Johan Rudholm
2013-02-28 13:23 ` Philip Rakity
2013-03-22 16:21 ` Chris Ball
2 siblings, 1 reply; 5+ messages in thread
From: Ulf Hansson @ 2013-02-28 8:46 UTC (permalink / raw)
To: Kevin Liu
Cc: linux-mmc, Chris Ball, Guennadi Liakhovetski, Sujit Reddy Thumma,
Jaehoon Chung, Aaron Lu, Wei WANG, Fabio Estevam, Stephen Warren,
Adrian Hunter, Philip Rakity, Shawn Guo, Johan Rudholm,
Girish K S, Haijun Zhang, Zhangfei Gao, Haojian Zhuang, Chao Xie,
Kevin Liu
On 28 February 2013 08:29, Kevin Liu <kliu5@marvell.com> wrote:
> Function _mmc_detect_card_removed will be called to know whether
> the card is still present when host->bus_ops->detect is called.
> In current code, the return value of this function generally only
> depend on the result of sending cmd13 to card, which may not safe
> for card with detection support like slot gpio detection.
> Because the communication status between host and card may out of
> sync with the detect status if remove the card slowly or hands shake
> during the process. The direct reason is the async between card
> detect switch and card/slot pad contaction in hardware, which is
> defined by spec.
>
> The spec define card insert/remove sequence as below (both standard size
> SD card and MicroSD card have the same sequence):
> "Part 1 Standard Size SD Card Mechanical Addendum Ver4.00 Final,
> Appendix C: Card Detection Switch" (Take normally open type as example)
> a)SD card insertion sequence:
> The card detection switch should be turned on after all SD card
> contact pads are connected to the host connector contact pads.
> b)SD removal sequence:
> The card detection switch should be turned off when the SD card
> is just going to be removed and before any SD card contact pad is
> disconnected from the host connector contact pad.
>
> Below is the sequence when this issue occur (Take slot gpio detection
> as example and remove the card slowly during the process):
> 1. gpio level changed and card detect interrupt triggered.
> 2. mmc_rescan was launched.
> 3. the card pads were still contacted with the slot pads because of slow
> removal. So _mmc_detect_card_removed and mmc_rescan think card was
> still present (cmd13 succeed).
> 4. card pads were discontacted from the card slot pads.
> So the card was actually removed finally but the card removal event
> has been missed by system.
> The interval length between step 1 and step 4 depends on the
> card removal speed. If it's longer than the detect work schedule
> delay which is 200ms, this issue will likely happen.
>
> This patch add the card detect status check in function
> _mmc_detect_card_removed if cmd13 check succeed and host->ops->get_cd
> provided. If get_cd detect no card present then schedule another detect
> work 200ms later.
>
> Signed-off-by: Kevin Liu <kliu5@marvell.com>
> ---
> drivers/mmc/core/core.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index b8c3d41..d9ac96c 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2290,6 +2290,19 @@ int _mmc_detect_card_removed(struct mmc_host *host)
> return 1;
>
> ret = host->bus_ops->alive(host);
> + /*
> + * Card detect status and alive check may out of sync if card is
> + * removed slowly when card detect switch changed while card/slot
> + * pads still contacted in hardware.(refer to "SD Card Mechanical
> + * Addendum, Appendix C: Card Detection Switch") So reschedule a
> + * detect work 200ms later for this case.
> + */
> + if (!ret && host->ops->get_cd && !host->ops->get_cd(host)) {
> + mmc_detect_change(host, msecs_to_jiffies(200));
> + pr_debug("%s: card remove too slowly\n",
> + mmc_hostname(host));
> + }
> +
> if (ret) {
> mmc_card_set_removed(host->card);
> pr_debug("%s: card remove detected\n", mmc_hostname(host));
> --
> 1.7.9.5
>
Great work Kevin and thanks for convincing me around this patch! :-)
I also intend to remove the MMC_CAP2_DETECT_ON_ERR code, I don't see a
need for it anymore.
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal
2013-02-28 8:46 ` Ulf Hansson
@ 2013-02-28 9:34 ` Johan Rudholm
0 siblings, 0 replies; 5+ messages in thread
From: Johan Rudholm @ 2013-02-28 9:34 UTC (permalink / raw)
To: Ulf Hansson
Cc: Kevin Liu, linux-mmc, Chris Ball, Guennadi Liakhovetski,
Sujit Reddy Thumma, Jaehoon Chung, Aaron Lu, Wei WANG,
Fabio Estevam, Stephen Warren, Adrian Hunter, Philip Rakity,
Shawn Guo, Johan Rudholm, Girish K S, Haijun Zhang, Zhangfei Gao,
Haojian Zhuang, Chao Xie, Kevin Liu
Hi,
2013/2/28 Ulf Hansson <ulf.hansson@linaro.org>:
> On 28 February 2013 08:29, Kevin Liu <kliu5@marvell.com> wrote:
>> Function _mmc_detect_card_removed will be called to know whether
>> the card is still present when host->bus_ops->detect is called.
>> In current code, the return value of this function generally only
>> depend on the result of sending cmd13 to card, which may not safe
>> for card with detection support like slot gpio detection.
>> Because the communication status between host and card may out of
>> sync with the detect status if remove the card slowly or hands shake
>> during the process. The direct reason is the async between card
>> detect switch and card/slot pad contaction in hardware, which is
>> defined by spec.
>>
>> The spec define card insert/remove sequence as below (both standard size
>> SD card and MicroSD card have the same sequence):
>> "Part 1 Standard Size SD Card Mechanical Addendum Ver4.00 Final,
>> Appendix C: Card Detection Switch" (Take normally open type as example)
>> a)SD card insertion sequence:
>> The card detection switch should be turned on after all SD card
>> contact pads are connected to the host connector contact pads.
>> b)SD removal sequence:
>> The card detection switch should be turned off when the SD card
>> is just going to be removed and before any SD card contact pad is
>> disconnected from the host connector contact pad.
>>
>> Below is the sequence when this issue occur (Take slot gpio detection
>> as example and remove the card slowly during the process):
>> 1. gpio level changed and card detect interrupt triggered.
>> 2. mmc_rescan was launched.
>> 3. the card pads were still contacted with the slot pads because of slow
>> removal. So _mmc_detect_card_removed and mmc_rescan think card was
>> still present (cmd13 succeed).
>> 4. card pads were discontacted from the card slot pads.
>> So the card was actually removed finally but the card removal event
>> has been missed by system.
>> The interval length between step 1 and step 4 depends on the
>> card removal speed. If it's longer than the detect work schedule
>> delay which is 200ms, this issue will likely happen.
>>
>> This patch add the card detect status check in function
>> _mmc_detect_card_removed if cmd13 check succeed and host->ops->get_cd
>> provided. If get_cd detect no card present then schedule another detect
>> work 200ms later.
>>
>> Signed-off-by: Kevin Liu <kliu5@marvell.com>
>> ---
>> drivers/mmc/core/core.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index b8c3d41..d9ac96c 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -2290,6 +2290,19 @@ int _mmc_detect_card_removed(struct mmc_host *host)
>> return 1;
>>
>> ret = host->bus_ops->alive(host);
>> + /*
>> + * Card detect status and alive check may out of sync if card is
>> + * removed slowly when card detect switch changed while card/slot
>> + * pads still contacted in hardware.(refer to "SD Card Mechanical
>> + * Addendum, Appendix C: Card Detection Switch") So reschedule a
>> + * detect work 200ms later for this case.
>> + */
>> + if (!ret && host->ops->get_cd && !host->ops->get_cd(host)) {
>> + mmc_detect_change(host, msecs_to_jiffies(200));
>> + pr_debug("%s: card remove too slowly\n",
>> + mmc_hostname(host));
>> + }
>> +
>> if (ret) {
>> mmc_card_set_removed(host->card);
>> pr_debug("%s: card remove detected\n", mmc_hostname(host));
>> --
>> 1.7.9.5
>>
>
> Great work Kevin and thanks for convincing me around this patch! :-)
>
> I also intend to remove the MMC_CAP2_DETECT_ON_ERR code, I don't see a
> need for it anymore.
>
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
and
Tested-by: Johan Rudholm <johan.rudholm@stericsson.com>
//Johan
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal
2013-02-28 7:29 [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal Kevin Liu
2013-02-28 8:46 ` Ulf Hansson
@ 2013-02-28 13:23 ` Philip Rakity
2013-03-22 16:21 ` Chris Ball
2 siblings, 0 replies; 5+ messages in thread
From: Philip Rakity @ 2013-02-28 13:23 UTC (permalink / raw)
To: Kevin Liu
Cc: linux-mmc@vger.kernel.org, Chris Ball, Guennadi Liakhovetski,
Sujit Reddy Thumma, Jaehoon Chung, Aaron Lu, Ulf Hansson,
Wei WANG, Fabio Estevam, Stephen Warren, Adrian Hunter, Shawn Guo,
Johan Rudholm, Girish K S, Haijun Zhang, Zhangfei Gao,
Haojian Zhuang, Chao Xie, Kevin Liu
Reviewed-by: Philip Rakity <prakity@nvidia.com>
On Feb 28, 2013, at 7:29 AM, Kevin Liu <kliu5@marvell.com> wrote:
> Function _mmc_detect_card_removed will be called to know whether
> the card is still present when host->bus_ops->detect is called.
> In current code, the return value of this function generally only
> depend on the result of sending cmd13 to card, which may not safe
> for card with detection support like slot gpio detection.
> Because the communication status between host and card may out of
> sync with the detect status if remove the card slowly or hands shake
> during the process. The direct reason is the async between card
> detect switch and card/slot pad contaction in hardware, which is
> defined by spec.
>
> The spec define card insert/remove sequence as below (both standard size
> SD card and MicroSD card have the same sequence):
> "Part 1 Standard Size SD Card Mechanical Addendum Ver4.00 Final,
> Appendix C: Card Detection Switch" (Take normally open type as example)
> a)SD card insertion sequence:
> The card detection switch should be turned on after all SD card
> contact pads are connected to the host connector contact pads.
> b)SD removal sequence:
> The card detection switch should be turned off when the SD card
> is just going to be removed and before any SD card contact pad is
> disconnected from the host connector contact pad.
>
> Below is the sequence when this issue occur (Take slot gpio detection
> as example and remove the card slowly during the process):
> 1. gpio level changed and card detect interrupt triggered.
> 2. mmc_rescan was launched.
> 3. the card pads were still contacted with the slot pads because of slow
> removal. So _mmc_detect_card_removed and mmc_rescan think card was
> still present (cmd13 succeed).
> 4. card pads were discontacted from the card slot pads.
> So the card was actually removed finally but the card removal event
> has been missed by system.
> The interval length between step 1 and step 4 depends on the
> card removal speed. If it's longer than the detect work schedule
> delay which is 200ms, this issue will likely happen.
>
> This patch add the card detect status check in function
> _mmc_detect_card_removed if cmd13 check succeed and host->ops->get_cd
> provided. If get_cd detect no card present then schedule another detect
> work 200ms later.
>
> Signed-off-by: Kevin Liu <kliu5@marvell.com>
> ---
> drivers/mmc/core/core.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index b8c3d41..d9ac96c 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2290,6 +2290,19 @@ int _mmc_detect_card_removed(struct mmc_host *host)
> return 1;
>
> ret = host->bus_ops->alive(host);
> + /*
> + * Card detect status and alive check may out of sync if card is
> + * removed slowly when card detect switch changed while card/slot
> + * pads still contacted in hardware.(refer to "SD Card Mechanical
> + * Addendum, Appendix C: Card Detection Switch") So reschedule a
> + * detect work 200ms later for this case.
> + */
> + if (!ret && host->ops->get_cd && !host->ops->get_cd(host)) {
> + mmc_detect_change(host, msecs_to_jiffies(200));
> + pr_debug("%s: card remove too slowly\n",
> + mmc_hostname(host));
> + }
> +
> if (ret) {
> mmc_card_set_removed(host->card);
> pr_debug("%s: card remove detected\n", mmc_hostname(host));
> --
> 1.7.9.5
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal
2013-02-28 7:29 [PATCH v7 1/2] mmc: core: enhance card removal judgement for slow removal Kevin Liu
2013-02-28 8:46 ` Ulf Hansson
2013-02-28 13:23 ` Philip Rakity
@ 2013-03-22 16:21 ` Chris Ball
2 siblings, 0 replies; 5+ messages in thread
From: Chris Ball @ 2013-03-22 16:21 UTC (permalink / raw)
To: Kevin Liu
Cc: linux-mmc, Guennadi Liakhovetski, Sujit Reddy Thumma,
Jaehoon Chung, Aaron Lu, Ulf Hansson, Wei WANG, Fabio Estevam,
Stephen Warren, Adrian Hunter, Philip Rakity, Shawn Guo,
Johan Rudholm, Girish K S, Haijun Zhang, Zhangfei Gao,
Haojian Zhuang, Chao Xie, Kevin Liu
Hi,
On Thu, Feb 28 2013, Kevin Liu wrote:
> Function _mmc_detect_card_removed will be called to know whether
> the card is still present when host->bus_ops->detect is called.
> In current code, the return value of this function generally only
> depend on the result of sending cmd13 to card, which may not safe
> for card with detection support like slot gpio detection.
> Because the communication status between host and card may out of
> sync with the detect status if remove the card slowly or hands shake
> during the process. The direct reason is the async between card
> detect switch and card/slot pad contaction in hardware, which is
> defined by spec.
>
> The spec define card insert/remove sequence as below (both standard size
> SD card and MicroSD card have the same sequence):
> "Part 1 Standard Size SD Card Mechanical Addendum Ver4.00 Final,
> Appendix C: Card Detection Switch" (Take normally open type as example)
> a)SD card insertion sequence:
> The card detection switch should be turned on after all SD card
> contact pads are connected to the host connector contact pads.
> b)SD removal sequence:
> The card detection switch should be turned off when the SD card
> is just going to be removed and before any SD card contact pad is
> disconnected from the host connector contact pad.
>
> Below is the sequence when this issue occur (Take slot gpio detection
> as example and remove the card slowly during the process):
> 1. gpio level changed and card detect interrupt triggered.
> 2. mmc_rescan was launched.
> 3. the card pads were still contacted with the slot pads because of slow
> removal. So _mmc_detect_card_removed and mmc_rescan think card was
> still present (cmd13 succeed).
> 4. card pads were discontacted from the card slot pads.
> So the card was actually removed finally but the card removal event
> has been missed by system.
> The interval length between step 1 and step 4 depends on the
> card removal speed. If it's longer than the detect work schedule
> delay which is 200ms, this issue will likely happen.
>
> This patch add the card detect status check in function
> _mmc_detect_card_removed if cmd13 check succeed and host->ops->get_cd
> provided. If get_cd detect no card present then schedule another detect
> work 200ms later.
>
> Signed-off-by: Kevin Liu <kliu5@marvell.com>
Thanks, pushed to mmc-next for 3.10.
- Chris.
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child
^ permalink raw reply [flat|nested] 5+ messages in thread