[PATCH v2 0/2] rtsx_usb: fix tray-reader false card detect and autosuspend

[PATCH v2 0/2] rtsx_usb: fix tray-reader false card detect and autosuspend

[Sean Rhodes]

This series fixes the empty-tray detect loop seen on a Realtek RTS5129
USB SD reader, while also avoiding USB register accesses from the USB
runtime autosuspend callback.

Compared with the previous RFC, this no longer qualifies media by issuing
SD/MMC commands from ->get_cd().  The rtsx_usb_sdmmc child still reports
the raw card-detect state initially, then lets the normal MMC rescan path
probe the media.  If an initialization command times out before a card is
attached, the SD child suppresses the raw SD_CD signal until the tray/card
detect line drops again.

The parent rtsx_usb change removes USB I/O from runtime autosuspend and
keeps only the existing Memory Stick autosuspend deferral based on cached
card-status bits.  Raw SD_CD is not used as a parent autosuspend blocker,
because this reader can assert it for an empty tray.

Runtime-tested on a StarLite Mk V with Realtek RTS5129 (0bda:0129), using
these changes as a matched rtsx_usb/rtsx_usb_sdmmc/rtsx_usb_ms module set
on Linux 7.0.0-27-generic.

Device enumeration:
  Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
  /:  Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/12p, 480M
      |__ Port 004: Dev 003, If 0, Class=Vendor Specific Class, Driver=rtsx_usb, 480M

Card inserted:
  mmc0: new UHS-I speed SDR50 SDXC card at address 544c
  mmcblk0: mmc0:544c LX2TB 1.82 TiB
   mmcblk0: p1

Deep S3 with the card inserted:
  PM: suspend entry (deep)
  ACPI: PM: Waking up from system sleep state S3
  PM: suspend exit

After resume, the card remained visible:
  NAME         SIZE TYPE FSTYPE MOUNTPOINTS
  mmcblk0      1.8T disk
  `-mmcblk0p1  1.8T part exfat

Empty tray:
  mmc0: card 544c removed
  /sys/bus/usb/devices/1-4/power/control=auto
  /sys/bus/usb/devices/1-4/power/runtime_status=suspended
  /sys/bus/usb/devices/1-4/power/runtime_usage=0

With the empty tray left inserted for about three minutes, no repeated
MMC detect attempts, command timeouts, or USB reset churn were observed.

Sean Rhodes (2):
  misc: rtsx_usb: avoid USB I/O in runtime autosuspend
  mmc: rtsx_usb_sdmmc: suppress false CD after init timeout

 drivers/misc/cardreader/rtsx_usb.c | 26 ++++++++++++++++++++------
 drivers/mmc/host/rtsx_usb_sdmmc.c  | 13 ++++++++++++-
 include/linux/rtsx_usb.h           |  3 +++
 3 files changed, 35 insertions(+), 7 deletions(-)

[PATCH v2 1/2] misc: rtsx_usb: avoid USB I/O in runtime autosuspend

[Sean Rhodes]

The runtime autosuspend callback currently queries card status and
clears OCP by issuing USB register accesses. This can run from the
USB runtime-PM path itself, which is the wrong place to start more
device I/O.

Keep a cached copy of the card-status bits from normal status reads
instead. During runtime autosuspend, use that cached value only to
preserve the existing Memory Stick autosuspend deferral.

Do not treat raw SD_CD as an autosuspend blocker, because tray-based
SD readers can assert SD_CD with an empty tray. A real SD card is
protected by the SD/MMC child runtime-PM usage once powered.

Also stop clearing OCP from the runtime autosuspend callback, so the
callback does not issue USB commands.

Fixes: bb400d2120bd ("mfd: rtsx_usb: Defer autosuspend while card exists")

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
---
 drivers/misc/cardreader/rtsx_usb.c | 26 ++++++++++++++++++++------
 include/linux/rtsx_usb.h           |  3 +++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index 1830e9ed2521..a127744918f4 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -312,6 +312,9 @@ int rtsx_usb_get_card_status(struct rtsx_ucr *ucr, u16 *status)
 	if (ret < 0)
 		return ret;
 
+	ucr->card_status_cache = *status;
+	ucr->card_status_valid = true;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rtsx_usb_get_card_status);
@@ -623,6 +626,7 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 {
 	struct usb_device *usb_dev = interface_to_usbdev(intf);
 	struct rtsx_ucr *ucr;
+	u16 status;
 	int ret;
 
 	dev_dbg(&intf->dev,
@@ -659,6 +663,9 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 	if (ret)
 		goto out_init_fail;
 
+	/* Prime cached status for runtime autosuspend decisions. */
+	rtsx_usb_get_card_status(ucr, &status);
+
 	/* initialize USB SG transfer timer */
 	timer_setup(&ucr->sg_timer, rtsx_usb_sg_timed_out, 0);
 
@@ -713,22 +720,29 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 	struct rtsx_ucr *ucr =
 		(struct rtsx_ucr *)usb_get_intfdata(intf);
 	u16 val = 0;
+	bool valid = false;
 
 	dev_dbg(&intf->dev, "%s called with pm message 0x%04x\n",
 			__func__, message.event);
 
 	if (PMSG_IS_AUTO(message)) {
 		if (mutex_trylock(&ucr->dev_mutex)) {
-			rtsx_usb_get_card_status(ucr, &val);
+			valid = ucr->card_status_valid;
+			if (valid)
+				val = ucr->card_status_cache;
 			mutex_unlock(&ucr->dev_mutex);
 
-			/* Defer the autosuspend if card exists */
-			if (val & (SD_CD | MS_CD)) {
+			/*
+			 * Do not issue USB commands from runtime autosuspend.
+			 * Raw SD_CD is not authoritative on tray-based readers,
+			 * while a real SD card is protected by the SD/MMC child
+			 * runtime-PM reference once the card is powered. Keep
+			 * the historical Memory Stick autosuspend deferral when
+			 * the cached status says MS media is present.
+			 */
+			if (valid && (val & MS_CD)) {
 				device_for_each_child(&intf->dev, NULL, rtsx_usb_resume_child);
 				return -EAGAIN;
-			} else {
-				/* if the card does not exists, clear OCP status */
-				rtsx_usb_write_register(ucr, OCPCTL, MS_OCP_CLEAR, MS_OCP_CLEAR);
 			}
 		} else {
 			/* There is an ongoing operation*/
diff --git a/include/linux/rtsx_usb.h b/include/linux/rtsx_usb.h
index 276b509c03e3..0fc5a74700a8 100644
--- a/include/linux/rtsx_usb.h
+++ b/include/linux/rtsx_usb.h
@@ -61,6 +61,9 @@ struct rtsx_ucr {
 
 	struct timer_list	sg_timer;
 	struct mutex		dev_mutex;
+
+	u16			card_status_cache;
+	bool			card_status_valid;
 };
 
 /* buffer size */

[PATCH v2 2/2] mmc: rtsx_usb_sdmmc: suppress false CD after init timeout

[Sean Rhodes]

Some Realtek USB SD readers with a tray keep raw SD_CD asserted
when an empty tray is inserted. The MMC core then repeatedly tries to
initialize non-existent media, sees command timeouts, calls ->get_cd()
again, and starts the same detect cycle over.

Do not qualify media by open-coding MMC commands in ->get_cd().
Instead, let the normal MMC rescan path probe the card. If an
initialization command times out before a card has been attached,
suppress the raw SD_CD signal so the host can settle and the USB
parent can autosuspend.

Clear the suppression only when raw SD_CD drops. On the affected tray
reader, changing media requires removing and reinserting the tray, so
a low CD transition is the signal that a new insertion attempt can be
trusted again.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
---
 drivers/mmc/host/rtsx_usb_sdmmc.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c
index 84674659a84d..bf37fab233cf 100644
--- a/drivers/mmc/host/rtsx_usb_sdmmc.c
+++ b/drivers/mmc/host/rtsx_usb_sdmmc.c
@@ -44,6 +44,7 @@ struct rtsx_usb_sdmmc {
 	bool			double_clk;
 	bool			host_removal;
 	bool			card_exist;
+	bool			suppress_cd;
 	bool			initial_mode;
 	bool			ddr_mode;
 
@@ -774,6 +775,7 @@ static int sdmmc_get_cd(struct mmc_host *mmc)
 	struct rtsx_ucr *ucr = host->ucr;
 	int err;
 	u16 val;
+	bool cd;
 
 	if (host->host_removal)
 		return -ENOMEDIUM;
@@ -791,8 +793,14 @@ static int sdmmc_get_cd(struct mmc_host *mmc)
 
 	/* get OCP status */
 	host->ocp_stat = (val >> 4) & 0x03;
+	cd = val & SD_CD;
 
-	if (val & SD_CD) {
+	if (!cd) {
+		WRITE_ONCE(host->suppress_cd, false);
+		goto no_card;
+	}
+
+	if (!READ_ONCE(host->suppress_cd)) {
 		host->card_exist = true;
 		return 1;
 	}
@@ -874,6 +882,8 @@ static void sdmmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		 * detect card when fail to update card existence state and
 		 * speed up card removal when retry
 		 */
+		if (!mmc->card && cmd->error == -ETIMEDOUT)
+			WRITE_ONCE(host->suppress_cd, true);
 		sdmmc_get_cd(mmc);
 		dev_dbg(sdmmc_dev(host), "cmd->error = %d\n", cmd->error);
 	}
@@ -1359,6 +1369,7 @@ static void rtsx_usb_init_host(struct rtsx_usb_sdmmc *host)
 
 	host->power_mode = MMC_POWER_OFF;
 	host->ocp_stat = 0;
+	host->suppress_cd = false;
 }
 
 static int rtsx_usb_sdmmc_drv_probe(struct platform_device *pdev)

Re: [PATCH v2 0/2] rtsx_usb: fix tray-reader false card detect and autosuspend

[Ulf Hansson]

On Mon, Jul 6, 2026 at 5:40 PM Sean Rhodes <sean@starlabs.systems> wrote:
>
> This series fixes the empty-tray detect loop seen on a Realtek RTS5129
> USB SD reader, while also avoiding USB register accesses from the USB
> runtime autosuspend callback.
>
> Compared with the previous RFC, this no longer qualifies media by issuing
> SD/MMC commands from ->get_cd().  The rtsx_usb_sdmmc child still reports
> the raw card-detect state initially, then lets the normal MMC rescan path
> probe the media.  If an initialization command times out before a card is
> attached, the SD child suppresses the raw SD_CD signal until the tray/card
> detect line drops again.
>
> The parent rtsx_usb change removes USB I/O from runtime autosuspend and
> keeps only the existing Memory Stick autosuspend deferral based on cached
> card-status bits.  Raw SD_CD is not used as a parent autosuspend blocker,
> because this reader can assert it for an empty tray.
>
> Runtime-tested on a StarLite Mk V with Realtek RTS5129 (0bda:0129), using
> these changes as a matched rtsx_usb/rtsx_usb_sdmmc/rtsx_usb_ms module set
> on Linux 7.0.0-27-generic.
>
> Device enumeration:
>   Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
>   /:  Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/12p, 480M
>       |__ Port 004: Dev 003, If 0, Class=Vendor Specific Class, Driver=rtsx_usb, 480M
>
> Card inserted:
>   mmc0: new UHS-I speed SDR50 SDXC card at address 544c
>   mmcblk0: mmc0:544c LX2TB 1.82 TiB
>    mmcblk0: p1
>
> Deep S3 with the card inserted:
>   PM: suspend entry (deep)
>   ACPI: PM: Waking up from system sleep state S3
>   PM: suspend exit
>
> After resume, the card remained visible:
>   NAME         SIZE TYPE FSTYPE MOUNTPOINTS
>   mmcblk0      1.8T disk
>   `-mmcblk0p1  1.8T part exfat
>
> Empty tray:
>   mmc0: card 544c removed
>   /sys/bus/usb/devices/1-4/power/control=auto
>   /sys/bus/usb/devices/1-4/power/runtime_status=suspended
>   /sys/bus/usb/devices/1-4/power/runtime_usage=0
>
> With the empty tray left inserted for about three minutes, no repeated
> MMC detect attempts, command timeouts, or USB reset churn were observed.
>
> Sean Rhodes (2):
>   misc: rtsx_usb: avoid USB I/O in runtime autosuspend
>   mmc: rtsx_usb_sdmmc: suppress false CD after init timeout
>
>  drivers/misc/cardreader/rtsx_usb.c | 26 ++++++++++++++++++++------
>  drivers/mmc/host/rtsx_usb_sdmmc.c  | 13 ++++++++++++-
>  include/linux/rtsx_usb.h           |  3 +++
>  3 files changed, 35 insertions(+), 7 deletions(-)
>

I decided to queue the series for next to get it thoroughly tested.
Potentially we should also tag these for stable kernels, but let's get
it tested a bit more in next first.

Greg, please let me know if you have any objections that I pick this
via my mmc tree, or please provide your ack.

Kind regards
Uffe

Re: [PATCH v2 0/2] rtsx_usb: fix tray-reader false card detect and autosuspend

[Greg Kroah-Hartman]

On Fri, Jul 10, 2026 at 03:21:51PM +0200, Ulf Hansson wrote:
> On Mon, Jul 6, 2026 at 5:40 PM Sean Rhodes <sean@starlabs.systems> wrote:
> >
> > This series fixes the empty-tray detect loop seen on a Realtek RTS5129
> > USB SD reader, while also avoiding USB register accesses from the USB
> > runtime autosuspend callback.
> >
> > Compared with the previous RFC, this no longer qualifies media by issuing
> > SD/MMC commands from ->get_cd().  The rtsx_usb_sdmmc child still reports
> > the raw card-detect state initially, then lets the normal MMC rescan path
> > probe the media.  If an initialization command times out before a card is
> > attached, the SD child suppresses the raw SD_CD signal until the tray/card
> > detect line drops again.
> >
> > The parent rtsx_usb change removes USB I/O from runtime autosuspend and
> > keeps only the existing Memory Stick autosuspend deferral based on cached
> > card-status bits.  Raw SD_CD is not used as a parent autosuspend blocker,
> > because this reader can assert it for an empty tray.
> >
> > Runtime-tested on a StarLite Mk V with Realtek RTS5129 (0bda:0129), using
> > these changes as a matched rtsx_usb/rtsx_usb_sdmmc/rtsx_usb_ms module set
> > on Linux 7.0.0-27-generic.
> >
> > Device enumeration:
> >   Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
> >   /:  Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/12p, 480M
> >       |__ Port 004: Dev 003, If 0, Class=Vendor Specific Class, Driver=rtsx_usb, 480M
> >
> > Card inserted:
> >   mmc0: new UHS-I speed SDR50 SDXC card at address 544c
> >   mmcblk0: mmc0:544c LX2TB 1.82 TiB
> >    mmcblk0: p1
> >
> > Deep S3 with the card inserted:
> >   PM: suspend entry (deep)
> >   ACPI: PM: Waking up from system sleep state S3
> >   PM: suspend exit
> >
> > After resume, the card remained visible:
> >   NAME         SIZE TYPE FSTYPE MOUNTPOINTS
> >   mmcblk0      1.8T disk
> >   `-mmcblk0p1  1.8T part exfat
> >
> > Empty tray:
> >   mmc0: card 544c removed
> >   /sys/bus/usb/devices/1-4/power/control=auto
> >   /sys/bus/usb/devices/1-4/power/runtime_status=suspended
> >   /sys/bus/usb/devices/1-4/power/runtime_usage=0
> >
> > With the empty tray left inserted for about three minutes, no repeated
> > MMC detect attempts, command timeouts, or USB reset churn were observed.
> >
> > Sean Rhodes (2):
> >   misc: rtsx_usb: avoid USB I/O in runtime autosuspend
> >   mmc: rtsx_usb_sdmmc: suppress false CD after init timeout
> >
> >  drivers/misc/cardreader/rtsx_usb.c | 26 ++++++++++++++++++++------
> >  drivers/mmc/host/rtsx_usb_sdmmc.c  | 13 ++++++++++++-
> >  include/linux/rtsx_usb.h           |  3 +++
> >  3 files changed, 35 insertions(+), 7 deletions(-)
> >
> 
> I decided to queue the series for next to get it thoroughly tested.
> Potentially we should also tag these for stable kernels, but let's get
> it tested a bit more in next first.
> 
> Greg, please let me know if you have any objections that I pick this
> via my mmc tree, or please provide your ack.

No objection from me:

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH v2 1/2] misc: rtsx_usb: avoid USB I/O in runtime autosuspend

[Michal Pecio]

On Mon,  6 Jul 2026 16:40:43 +0100, Sean Rhodes wrote:
> The runtime autosuspend callback currently queries card status and
> clears OCP by issuing USB register accesses. This can run from the
> USB runtime-PM path itself, which is the wrong place to start more
> device I/O.
> 
> Keep a cached copy of the card-status bits from normal status reads
> instead. During runtime autosuspend, use that cached value only to
> preserve the existing Memory Stick autosuspend deferral.

How is the driver supposed to detect card insertion after the last poll
but before the reader goes to suspend and can issue remote wakeup?

This is exactly what happens now: if I insert a new card within two
seconds of the "card removed" message showing up (which itself happens
up to a second after removal) the insertion is never detected and the
reader enters suspend with the card in.

It seems that not only was "starting more I/O in the runtime-PM path"
actually a good idea, but polling should only stop when the parent USB
device suspends, not the child MMC host, because there is a two second
delay between them. And even with this patch reverted, insertion never
works if USB autosuspend is simply disabled altogether.

Also, does anyone know if there is any way to utilize the interrupt
endpoint instead of polling? I tried submitting a URB to it and got
regular responses, but only zeros. Can this be changed?

> Do not treat raw SD_CD as an autosuspend blocker, because tray-based
> SD readers can assert SD_CD with an empty tray. A real SD card is
> protected by the SD/MMC child runtime-PM usage once powered.

Sounds like the proper condition is to ignore the card if and only if
it failed to initialize and has not been swapped for a new one.

Hence the question about interrupts: this would vastly reduce the risk
that a swap for an actual working card remains undetected.

Regards,
Michal