[PATCH AUTOSEL 6.19-5.15] mmc: rtsx_pci: add quirk to disable MMC_CAP_AGGRESSIVE_PM for RTS525A

[PATCH AUTOSEL 6.19-5.15] mmc: rtsx_pci: add quirk to disable MMC_CAP_AGGRESSIVE_PM for RTS525A

[Sasha Levin]

From: Matthew Schwartz <matthew.schwartz@linux.dev>

[ Upstream commit 5f0bf80cc5e04d31eeb201683e0b477c24bd18e7 ]

Using MMC_CAP_AGGRESSIVE_PM on RTS525A card readers causes game
performance issues when the card reader comes back from idle into active
use. This can be observed in Hades II when loading new sections of the
game or menu after the card reader puts itself into idle, and presents
as a 1-2 second hang.

Add EXTRA_CAPS_NO_AGGRESSIVE_PM quirk to allow cardreader drivers to
opt-out of aggressive PM, and set it for RTS525A.

Closes: https://lore.kernel.org/linux-mmc/ff9a7c20-f465-4afa-bf29-708d4a52974a@linux.dev/
Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Link: https://patch.msgid.link/20260103204226.71752-1-matthew.schwartz@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

### Summary Analysis

**What the commit does:**
This commit adds a device-specific quirk for the Realtek RTS525A card
reader to disable `MMC_CAP_AGGRESSIVE_PM`. When aggressive PM is enabled
on this device, it powers down the card reader after 10 seconds of idle,
and re-tuning when waking up causes 1-2 second hangs that are user-
visible and impact performance.

**Does it fix a real bug?**
Yes. The aggressive PM behavior on RTS525A causes real, user-observable
1-2 second hangs during normal use. This was reported by a real user
with concrete reproduction steps (playing a game that loads data from a
micro SD card). The "Closes:" tag links to a real mailing list report.

**Stable kernel criteria assessment:**

1. **Obviously correct and tested**: The change follows an existing
   pattern (`EXTRA_CAPS_NO_MMC` is the exact same kind of quirk flag).
   The author tested it on affected hardware.

2. **Fixes a real bug**: Yes - user-visible performance degradation (1-2
   second hangs) on specific hardware.

3. **Important issue**: It's a usability issue rather than a
   crash/security issue. However, hardware quirks for broken behavior
   are explicitly allowed in stable.

4. **Small and contained**: The change is minimal - 3 new lines of code
   plus a new flag definition. It only affects RTS525A devices and
   doesn't change behavior for any other hardware.

5. **No new features**: This is a hardware quirk/workaround, which is an
   explicitly allowed exception to the "no new features" rule.

6. **Clean application**: The change builds on existing infrastructure
   (`extra_caps` flags) that exists in all stable trees since v5.11.

**Risk assessment:**
- **Very low risk**: The quirk only affects RTS525A devices
  (`PID_525A`). All other devices are completely unaffected.
- The code pattern is identical to existing quirks
  (`EXTRA_CAPS_NO_MMC`).
- The worst case if the quirk is wrong is slightly higher power
  consumption on RTS525A (no aggressive PM = card reader stays powered).

**Dependencies:**
None. The change uses existing infrastructure (`extra_caps`,
`CHK_PCI_PID`, `PID_525A`) that has been present since before v5.11.

### Verification

- **git log** showed `rtd3_en` / `MMC_CAP_AGGRESSIVE_PM` was introduced
  in commit `5b4258f6721f4` (v5.11), confirming all current stable trees
  have the affected code.
- **git tag --contains** confirmed the runtime PM commit is in stable
  trees (p-5.15, p-6.1, p-6.12).
- **Grep for EXTRA_CAPS_** confirmed the existing quirk flag pattern
  (NO_MMC at bit 7, SD_EXPRESS at bit 8, new flag at bit 9 - clean
  progression).
- **lore.kernel.org fetch** confirmed the bug report describes real
  user-reported 1-2 second hangs on RTS525A with concrete reproduction
  steps.
- **Code review** verified the change only adds a condition check and
  flag - no behavioral change for non-RTS525A devices.
- The commit was signed off by Greg Kroah-Hartman, the stable tree
  maintainer, indicating it went through proper review.
- Could NOT verify whether any stable tree has already picked this up
  (unverified, but not relevant to the YES/NO decision).

### Conclusion

This is a textbook hardware quirk for a specific device with a real,
user-reported issue. It follows existing patterns in the codebase, is
minimal in scope, and has zero risk to other devices. Hardware quirks
are explicitly listed as appropriate for stable backporting. The
affected code exists in all current stable trees (5.15+).

**YES**

 drivers/misc/cardreader/rts5249.c | 3 +++
 drivers/mmc/host/rtsx_pci_sdmmc.c | 4 ++--
 include/linux/rtsx_pci.h          | 1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/cardreader/rts5249.c b/drivers/misc/cardreader/rts5249.c
index 38aefd8db452a..87d576a03e68e 100644
--- a/drivers/misc/cardreader/rts5249.c
+++ b/drivers/misc/cardreader/rts5249.c
@@ -78,6 +78,9 @@ static void rtsx_base_fetch_vendor_settings(struct rtsx_pcr *pcr)
 	if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A))
 		pcr->rtd3_en = rtsx_reg_to_rtd3_uhsii(reg);
 
+	if (CHK_PCI_PID(pcr, PID_525A))
+		pcr->extra_caps |= EXTRA_CAPS_NO_AGGRESSIVE_PM;
+
 	if (rtsx_check_mmc_support(reg))
 		pcr->extra_caps |= EXTRA_CAPS_NO_MMC;
 	pcr->sd30_drive_sel_3v3 = rtsx_reg_to_sd30_drive_sel_3v3(reg);
diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index 4db3328f46dfb..8df60000b5b41 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -1497,8 +1497,8 @@ static void realtek_init_host(struct realtek_pci_sdmmc *host)
 	mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SD_HIGHSPEED |
 		MMC_CAP_MMC_HIGHSPEED | MMC_CAP_BUS_WIDTH_TEST |
 		MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
-	if (pcr->rtd3_en)
-		mmc->caps = mmc->caps | MMC_CAP_AGGRESSIVE_PM;
+	if (pcr->rtd3_en && !(pcr->extra_caps & EXTRA_CAPS_NO_AGGRESSIVE_PM))
+		mmc->caps |= MMC_CAP_AGGRESSIVE_PM;
 	mmc->caps2 = MMC_CAP2_NO_PRESCAN_POWERUP | MMC_CAP2_FULL_PWR_CYCLE |
 		MMC_CAP2_NO_SDIO;
 	mmc->max_current_330 = 400;
diff --git a/include/linux/rtsx_pci.h b/include/linux/rtsx_pci.h
index 3c5689356004e..f6122349c00ec 100644
--- a/include/linux/rtsx_pci.h
+++ b/include/linux/rtsx_pci.h
@@ -1230,6 +1230,7 @@ struct rtsx_pcr {
 #define EXTRA_CAPS_MMC_8BIT		(1 << 5)
 #define EXTRA_CAPS_NO_MMC		(1 << 7)
 #define EXTRA_CAPS_SD_EXPRESS		(1 << 8)
+#define EXTRA_CAPS_NO_AGGRESSIVE_PM	(1 << 9)
 	u32				extra_caps;
 
 #define IC_VER_A			0
-- 
2.51.0

[PATCH AUTOSEL 6.19-6.1] mmc: rtsx: reset power state on suspend

[Sasha Levin]

From: Matthew Schwartz <matthew.schwartz@linux.dev>

[ Upstream commit eac85fbd0867c25ac517f58fae401d65c627edff ]

When rtsx_pci suspends, the card reader hardware powers off but the sdmmc
driver's prev_power_state remains as MMC_POWER_ON. This causes sd_power_on
to skip reinitialization on the next I/O request, leading to DMA transfer
timeouts and errors on resume 20% of the time.

Add a power_off slot callback so the PCR can notify the sdmmc driver
during suspend. The sdmmc driver resets prev_power_state, and sd_request
checks this to reinitialize the card before the next I/O.

Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Link: https://patch.msgid.link/20260105060236.400366-2-matthew.schwartz@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

Good - `sd_power_on` has been part of this file since initial creation.
The forward declaration added in the patch is just to allow the function
(defined later in the file) to be called from `sd_request` (defined
earlier).

### Analysis Summary

**What problem the commit solves:**

This commit fixes a suspend/resume regression in Realtek PCI-E SD card
readers where, after suspend, 20% of resume attempts fail with DMA
transfer timeouts because:

1. During suspend, `rtsx_pci_power_off()` powers down the card reader
   hardware
2. But the sdmmc driver's `prev_power_state` remains `MMC_POWER_ON`
3. On resume, when `sd_power_on()` is called, it sees `prev_power_state
   == MMC_POWER_ON` at line 912 and returns immediately without
   reinitializing the hardware
4. The first I/O attempt then fails with DMA timeout because the
   hardware was never re-powered

**The fix has three parts:**
1. Adds a `power_off` callback to `struct rtsx_slot` (1 line in header)
2. In the PCR suspend paths (both system and runtime), calls
   `slot->power_off()` to notify the sdmmc driver before powering off
   hardware
3. In the sdmmc driver: implements `rtsx_pci_sdmmc_power_off()` to reset
   `prev_power_state = MMC_POWER_OFF`, and adds a check in
   `sd_request()` to call `sd_power_on()` if `prev_power_state ==
   MMC_POWER_OFF`

**Stable kernel criteria assessment:**
- **Fixes a real bug:** Yes - 20% failure rate on resume with SD card
  operations
- **Obviously correct:** Yes - the logic is straightforward: notify the
  driver that hardware was powered off so it reinitializes properly
- **Small and contained:** Yes - 32 lines of insertion across 3 files,
  all within the rtsx subsystem
- **No new features:** Correct - this adds only internal plumbing to fix
  power state tracking
- **Tested:** Author tested 300+ s2idle cycles
- **Impact:** Users with Realtek card readers experience I/O errors,
  filesystem journal failures, and card detection loss after
  suspend/resume

**Risk assessment:**
- Low risk - the changes are confined to the rtsx card reader subsystem
- The `power_off` callback is properly guarded with NULL checks (`if
  (slot->p_dev && slot->power_off)`)
- The `sd_request` power-on check has proper error handling
- The drv_remove function properly clears the callback
- No impact on other subsystems

**Dependencies:**
- Self-contained - no dependencies on other commits
- The companion delay patch (aced969e9bf37) has already been selected
  for stable and is independent
- The code being modified (`rtsx_slot`, `rtsx_pci_suspend`,
  `sd_request`) exists in all recent stable trees

### Verification

- **Verified** that `sd_power_on()` at line 912 returns early when
  `prev_power_state == MMC_POWER_ON`, confirming the bug mechanism
- **Verified** via `git show aced969e9bf37` that the companion patch
  (delay increase) has a Fixes: tag and was independently picked for
  stable
- **Verified** via `git show ed0d7f8559dbd` (stable branch version) that
  the delay patch was already applied to stable with `[Upstream commit
  ...]` marker
- **Verified** via lore.kernel.org that this is a 2-patch series (0/2
  cover letter), both fixing suspend/resume failures, with testing
  showing patch 1 reduces failures from 20% to 4%
- **Verified** that `struct rtsx_slot` currently only has `p_dev` and
  `card_event` fields by reading `include/linux/rtsx_common.h`
- **Verified** that the suspend paths properly hold `pcr->pcr_mutex`
  when calling the callback
- **Verified** the NULL check guards (`slot->p_dev && slot->power_off`)
  in both suspend functions
- **Verified** that `sd_power_on()` has existed since the driver was
  created (`ff984e57d36e8`) - the forward declaration is just for
  compilation order
- **Verified** that `rtsx_pci_sdmmc_drv_remove` properly clears
  `power_off = NULL` to prevent stale callbacks

This is a clear, well-tested bug fix for a user-impactful suspend/resume
issue. It's small, contained, properly guarded, and fixes a 20% failure
rate. It meets all stable kernel criteria.

**YES**

 drivers/misc/cardreader/rtsx_pcr.c |  9 +++++++++
 drivers/mmc/host/rtsx_pci_sdmmc.c  | 22 ++++++++++++++++++++++
 include/linux/rtsx_common.h        |  1 +
 3 files changed, 32 insertions(+)

diff --git a/drivers/misc/cardreader/rtsx_pcr.c b/drivers/misc/cardreader/rtsx_pcr.c
index f9952d76d6ed7..f1f4d8ed544d6 100644
--- a/drivers/misc/cardreader/rtsx_pcr.c
+++ b/drivers/misc/cardreader/rtsx_pcr.c
@@ -1654,6 +1654,7 @@ static int __maybe_unused rtsx_pci_suspend(struct device *dev_d)
 	struct pci_dev *pcidev = to_pci_dev(dev_d);
 	struct pcr_handle *handle = pci_get_drvdata(pcidev);
 	struct rtsx_pcr *pcr = handle->pcr;
+	struct rtsx_slot *slot = &pcr->slots[RTSX_SD_CARD];
 
 	dev_dbg(&(pcidev->dev), "--> %s\n", __func__);
 
@@ -1661,6 +1662,9 @@ static int __maybe_unused rtsx_pci_suspend(struct device *dev_d)
 
 	mutex_lock(&pcr->pcr_mutex);
 
+	if (slot->p_dev && slot->power_off)
+		slot->power_off(slot->p_dev);
+
 	rtsx_pci_power_off(pcr, HOST_ENTER_S3, false);
 
 	mutex_unlock(&pcr->pcr_mutex);
@@ -1772,12 +1776,17 @@ static int rtsx_pci_runtime_suspend(struct device *device)
 	struct pci_dev *pcidev = to_pci_dev(device);
 	struct pcr_handle *handle = pci_get_drvdata(pcidev);
 	struct rtsx_pcr *pcr = handle->pcr;
+	struct rtsx_slot *slot = &pcr->slots[RTSX_SD_CARD];
 
 	dev_dbg(device, "--> %s\n", __func__);
 
 	cancel_delayed_work_sync(&pcr->carddet_work);
 
 	mutex_lock(&pcr->pcr_mutex);
+
+	if (slot->p_dev && slot->power_off)
+		slot->power_off(slot->p_dev);
+
 	rtsx_pci_power_off(pcr, HOST_ENTER_S3, true);
 
 	mutex_unlock(&pcr->pcr_mutex);
diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index 8df60000b5b41..34343b5d5823d 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -47,6 +47,7 @@ struct realtek_pci_sdmmc {
 };
 
 static int sdmmc_init_sd_express(struct mmc_host *mmc, struct mmc_ios *ios);
+static int sd_power_on(struct realtek_pci_sdmmc *host, unsigned char power_mode);
 
 static inline struct device *sdmmc_dev(struct realtek_pci_sdmmc *host)
 {
@@ -821,6 +822,15 @@ static void sd_request(struct work_struct *work)
 
 	rtsx_pci_start_run(pcr);
 
+	if (host->prev_power_state == MMC_POWER_OFF) {
+		err = sd_power_on(host, MMC_POWER_ON);
+		if (err) {
+			cmd->error = err;
+			mutex_unlock(&pcr->pcr_mutex);
+			goto finish;
+		}
+	}
+
 	rtsx_pci_switch_clock(pcr, host->clock, host->ssc_depth,
 			host->initial_mode, host->double_clk, host->vpclk);
 	rtsx_pci_write_register(pcr, CARD_SELECT, 0x07, SD_MOD_SEL);
@@ -1522,6 +1532,16 @@ static void rtsx_pci_sdmmc_card_event(struct platform_device *pdev)
 	mmc_detect_change(host->mmc, 0);
 }
 
+static void rtsx_pci_sdmmc_power_off(struct platform_device *pdev)
+{
+	struct realtek_pci_sdmmc *host = platform_get_drvdata(pdev);
+
+	if (!host)
+		return;
+
+	host->prev_power_state = MMC_POWER_OFF;
+}
+
 static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
 {
 	struct mmc_host *mmc;
@@ -1554,6 +1574,7 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, host);
 	pcr->slots[RTSX_SD_CARD].p_dev = pdev;
 	pcr->slots[RTSX_SD_CARD].card_event = rtsx_pci_sdmmc_card_event;
+	pcr->slots[RTSX_SD_CARD].power_off = rtsx_pci_sdmmc_power_off;
 
 	mutex_init(&host->host_mutex);
 
@@ -1585,6 +1606,7 @@ static void rtsx_pci_sdmmc_drv_remove(struct platform_device *pdev)
 	pcr = host->pcr;
 	pcr->slots[RTSX_SD_CARD].p_dev = NULL;
 	pcr->slots[RTSX_SD_CARD].card_event = NULL;
+	pcr->slots[RTSX_SD_CARD].power_off = NULL;
 	mmc = host->mmc;
 
 	cancel_work_sync(&host->work);
diff --git a/include/linux/rtsx_common.h b/include/linux/rtsx_common.h
index da9c8c6b5d50f..f294f478f0c0e 100644
--- a/include/linux/rtsx_common.h
+++ b/include/linux/rtsx_common.h
@@ -32,6 +32,7 @@ struct platform_device;
 struct rtsx_slot {
 	struct platform_device	*p_dev;
 	void			(*card_event)(struct platform_device *p_dev);
+	void			(*power_off)(struct platform_device *p_dev);
 };
 
 #endif
-- 
2.51.0

Re: [PATCH AUTOSEL 6.19-6.1] mmc: rtsx: reset power state on suspend

[Ulf Hansson]

On Thu, 19 Feb 2026 at 03:04, Sasha Levin <sashal@kernel.org> wrote:
>
> From: Matthew Schwartz <matthew.schwartz@linux.dev>
>
> [ Upstream commit eac85fbd0867c25ac517f58fae401d65c627edff ]
>
> When rtsx_pci suspends, the card reader hardware powers off but the sdmmc
> driver's prev_power_state remains as MMC_POWER_ON. This causes sd_power_on
> to skip reinitialization on the next I/O request, leading to DMA transfer
> timeouts and errors on resume 20% of the time.
>
> Add a power_off slot callback so the PCR can notify the sdmmc driver
> during suspend. The sdmmc driver resets prev_power_state, and sd_request
> checks this to reinitialize the card before the next I/O.
>
> Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
> Link: https://patch.msgid.link/20260105060236.400366-2-matthew.schwartz@linux.dev
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

NAK.

This patch is reverted in mainline, as it's not the proper fix.

See commit c23f0550c05d40762b141808709667759291c938

Kind regards
Uffe

> ---
>
> LLM Generated explanations, may be completely bogus:
>
> Good - `sd_power_on` has been part of this file since initial creation.
> The forward declaration added in the patch is just to allow the function
> (defined later in the file) to be called from `sd_request` (defined
> earlier).
>
> ### Analysis Summary
>
> **What problem the commit solves:**
>
> This commit fixes a suspend/resume regression in Realtek PCI-E SD card
> readers where, after suspend, 20% of resume attempts fail with DMA
> transfer timeouts because:
>
> 1. During suspend, `rtsx_pci_power_off()` powers down the card reader
>    hardware
> 2. But the sdmmc driver's `prev_power_state` remains `MMC_POWER_ON`
> 3. On resume, when `sd_power_on()` is called, it sees `prev_power_state
>    == MMC_POWER_ON` at line 912 and returns immediately without
>    reinitializing the hardware
> 4. The first I/O attempt then fails with DMA timeout because the
>    hardware was never re-powered
>
> **The fix has three parts:**
> 1. Adds a `power_off` callback to `struct rtsx_slot` (1 line in header)
> 2. In the PCR suspend paths (both system and runtime), calls
>    `slot->power_off()` to notify the sdmmc driver before powering off
>    hardware
> 3. In the sdmmc driver: implements `rtsx_pci_sdmmc_power_off()` to reset
>    `prev_power_state = MMC_POWER_OFF`, and adds a check in
>    `sd_request()` to call `sd_power_on()` if `prev_power_state ==
>    MMC_POWER_OFF`
>
> **Stable kernel criteria assessment:**
> - **Fixes a real bug:** Yes - 20% failure rate on resume with SD card
>   operations
> - **Obviously correct:** Yes - the logic is straightforward: notify the
>   driver that hardware was powered off so it reinitializes properly
> - **Small and contained:** Yes - 32 lines of insertion across 3 files,
>   all within the rtsx subsystem
> - **No new features:** Correct - this adds only internal plumbing to fix
>   power state tracking
> - **Tested:** Author tested 300+ s2idle cycles
> - **Impact:** Users with Realtek card readers experience I/O errors,
>   filesystem journal failures, and card detection loss after
>   suspend/resume
>
> **Risk assessment:**
> - Low risk - the changes are confined to the rtsx card reader subsystem
> - The `power_off` callback is properly guarded with NULL checks (`if
>   (slot->p_dev && slot->power_off)`)
> - The `sd_request` power-on check has proper error handling
> - The drv_remove function properly clears the callback
> - No impact on other subsystems
>
> **Dependencies:**
> - Self-contained - no dependencies on other commits
> - The companion delay patch (aced969e9bf37) has already been selected
>   for stable and is independent
> - The code being modified (`rtsx_slot`, `rtsx_pci_suspend`,
>   `sd_request`) exists in all recent stable trees
>
> ### Verification
>
> - **Verified** that `sd_power_on()` at line 912 returns early when
>   `prev_power_state == MMC_POWER_ON`, confirming the bug mechanism
> - **Verified** via `git show aced969e9bf37` that the companion patch
>   (delay increase) has a Fixes: tag and was independently picked for
>   stable
> - **Verified** via `git show ed0d7f8559dbd` (stable branch version) that
>   the delay patch was already applied to stable with `[Upstream commit
>   ...]` marker
> - **Verified** via lore.kernel.org that this is a 2-patch series (0/2
>   cover letter), both fixing suspend/resume failures, with testing
>   showing patch 1 reduces failures from 20% to 4%
> - **Verified** that `struct rtsx_slot` currently only has `p_dev` and
>   `card_event` fields by reading `include/linux/rtsx_common.h`
> - **Verified** that the suspend paths properly hold `pcr->pcr_mutex`
>   when calling the callback
> - **Verified** the NULL check guards (`slot->p_dev && slot->power_off`)
>   in both suspend functions
> - **Verified** that `sd_power_on()` has existed since the driver was
>   created (`ff984e57d36e8`) - the forward declaration is just for
>   compilation order
> - **Verified** that `rtsx_pci_sdmmc_drv_remove` properly clears
>   `power_off = NULL` to prevent stale callbacks
>
> This is a clear, well-tested bug fix for a user-impactful suspend/resume
> issue. It's small, contained, properly guarded, and fixes a 20% failure
> rate. It meets all stable kernel criteria.
>
> **YES**
>
>  drivers/misc/cardreader/rtsx_pcr.c |  9 +++++++++
>  drivers/mmc/host/rtsx_pci_sdmmc.c  | 22 ++++++++++++++++++++++
>  include/linux/rtsx_common.h        |  1 +
>  3 files changed, 32 insertions(+)
>
> diff --git a/drivers/misc/cardreader/rtsx_pcr.c b/drivers/misc/cardreader/rtsx_pcr.c
> index f9952d76d6ed7..f1f4d8ed544d6 100644
> --- a/drivers/misc/cardreader/rtsx_pcr.c
> +++ b/drivers/misc/cardreader/rtsx_pcr.c
> @@ -1654,6 +1654,7 @@ static int __maybe_unused rtsx_pci_suspend(struct device *dev_d)
>         struct pci_dev *pcidev = to_pci_dev(dev_d);
>         struct pcr_handle *handle = pci_get_drvdata(pcidev);
>         struct rtsx_pcr *pcr = handle->pcr;
> +       struct rtsx_slot *slot = &pcr->slots[RTSX_SD_CARD];
>
>         dev_dbg(&(pcidev->dev), "--> %s\n", __func__);
>
> @@ -1661,6 +1662,9 @@ static int __maybe_unused rtsx_pci_suspend(struct device *dev_d)
>
>         mutex_lock(&pcr->pcr_mutex);
>
> +       if (slot->p_dev && slot->power_off)
> +               slot->power_off(slot->p_dev);
> +
>         rtsx_pci_power_off(pcr, HOST_ENTER_S3, false);
>
>         mutex_unlock(&pcr->pcr_mutex);
> @@ -1772,12 +1776,17 @@ static int rtsx_pci_runtime_suspend(struct device *device)
>         struct pci_dev *pcidev = to_pci_dev(device);
>         struct pcr_handle *handle = pci_get_drvdata(pcidev);
>         struct rtsx_pcr *pcr = handle->pcr;
> +       struct rtsx_slot *slot = &pcr->slots[RTSX_SD_CARD];
>
>         dev_dbg(device, "--> %s\n", __func__);
>
>         cancel_delayed_work_sync(&pcr->carddet_work);
>
>         mutex_lock(&pcr->pcr_mutex);
> +
> +       if (slot->p_dev && slot->power_off)
> +               slot->power_off(slot->p_dev);
> +
>         rtsx_pci_power_off(pcr, HOST_ENTER_S3, true);
>
>         mutex_unlock(&pcr->pcr_mutex);
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index 8df60000b5b41..34343b5d5823d 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -47,6 +47,7 @@ struct realtek_pci_sdmmc {
>  };
>
>  static int sdmmc_init_sd_express(struct mmc_host *mmc, struct mmc_ios *ios);
> +static int sd_power_on(struct realtek_pci_sdmmc *host, unsigned char power_mode);
>
>  static inline struct device *sdmmc_dev(struct realtek_pci_sdmmc *host)
>  {
> @@ -821,6 +822,15 @@ static void sd_request(struct work_struct *work)
>
>         rtsx_pci_start_run(pcr);
>
> +       if (host->prev_power_state == MMC_POWER_OFF) {
> +               err = sd_power_on(host, MMC_POWER_ON);
> +               if (err) {
> +                       cmd->error = err;
> +                       mutex_unlock(&pcr->pcr_mutex);
> +                       goto finish;
> +               }
> +       }
> +
>         rtsx_pci_switch_clock(pcr, host->clock, host->ssc_depth,
>                         host->initial_mode, host->double_clk, host->vpclk);
>         rtsx_pci_write_register(pcr, CARD_SELECT, 0x07, SD_MOD_SEL);
> @@ -1522,6 +1532,16 @@ static void rtsx_pci_sdmmc_card_event(struct platform_device *pdev)
>         mmc_detect_change(host->mmc, 0);
>  }
>
> +static void rtsx_pci_sdmmc_power_off(struct platform_device *pdev)
> +{
> +       struct realtek_pci_sdmmc *host = platform_get_drvdata(pdev);
> +
> +       if (!host)
> +               return;
> +
> +       host->prev_power_state = MMC_POWER_OFF;
> +}
> +
>  static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
>  {
>         struct mmc_host *mmc;
> @@ -1554,6 +1574,7 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
>         platform_set_drvdata(pdev, host);
>         pcr->slots[RTSX_SD_CARD].p_dev = pdev;
>         pcr->slots[RTSX_SD_CARD].card_event = rtsx_pci_sdmmc_card_event;
> +       pcr->slots[RTSX_SD_CARD].power_off = rtsx_pci_sdmmc_power_off;
>
>         mutex_init(&host->host_mutex);
>
> @@ -1585,6 +1606,7 @@ static void rtsx_pci_sdmmc_drv_remove(struct platform_device *pdev)
>         pcr = host->pcr;
>         pcr->slots[RTSX_SD_CARD].p_dev = NULL;
>         pcr->slots[RTSX_SD_CARD].card_event = NULL;
> +       pcr->slots[RTSX_SD_CARD].power_off = NULL;
>         mmc = host->mmc;
>
>         cancel_work_sync(&host->work);
> diff --git a/include/linux/rtsx_common.h b/include/linux/rtsx_common.h
> index da9c8c6b5d50f..f294f478f0c0e 100644
> --- a/include/linux/rtsx_common.h
> +++ b/include/linux/rtsx_common.h
> @@ -32,6 +32,7 @@ struct platform_device;
>  struct rtsx_slot {
>         struct platform_device  *p_dev;
>         void                    (*card_event)(struct platform_device *p_dev);
> +       void                    (*power_off)(struct platform_device *p_dev);
>  };
>
>  #endif
> --
> 2.51.0
>

Re: [PATCH AUTOSEL 6.19-5.15] mmc: rtsx_pci: add quirk to disable MMC_CAP_AGGRESSIVE_PM for RTS525A

[Ulf Hansson]

On Thu, 19 Feb 2026 at 03:04, Sasha Levin <sashal@kernel.org> wrote:
>
> From: Matthew Schwartz <matthew.schwartz@linux.dev>
>
> [ Upstream commit 5f0bf80cc5e04d31eeb201683e0b477c24bd18e7 ]
>
> Using MMC_CAP_AGGRESSIVE_PM on RTS525A card readers causes game
> performance issues when the card reader comes back from idle into active
> use. This can be observed in Hades II when loading new sections of the
> game or menu after the card reader puts itself into idle, and presents
> as a 1-2 second hang.
>
> Add EXTRA_CAPS_NO_AGGRESSIVE_PM quirk to allow cardreader drivers to
> opt-out of aggressive PM, and set it for RTS525A.
>
> Closes: https://lore.kernel.org/linux-mmc/ff9a7c20-f465-4afa-bf29-708d4a52974a@linux.dev/
> Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
> Link: https://patch.msgid.link/20260103204226.71752-1-matthew.schwartz@linux.dev
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

NAK.

This patch is reverted in mainline, as it's not the proper fix.

See commit eb89b17f283b233ba721fce358fa0d15223ae69d

Kind regards
Uffe




> ---
>
> LLM Generated explanations, may be completely bogus:
>
> ### Summary Analysis
>
> **What the commit does:**
> This commit adds a device-specific quirk for the Realtek RTS525A card
> reader to disable `MMC_CAP_AGGRESSIVE_PM`. When aggressive PM is enabled
> on this device, it powers down the card reader after 10 seconds of idle,
> and re-tuning when waking up causes 1-2 second hangs that are user-
> visible and impact performance.
>
> **Does it fix a real bug?**
> Yes. The aggressive PM behavior on RTS525A causes real, user-observable
> 1-2 second hangs during normal use. This was reported by a real user
> with concrete reproduction steps (playing a game that loads data from a
> micro SD card). The "Closes:" tag links to a real mailing list report.
>
> **Stable kernel criteria assessment:**
>
> 1. **Obviously correct and tested**: The change follows an existing
>    pattern (`EXTRA_CAPS_NO_MMC` is the exact same kind of quirk flag).
>    The author tested it on affected hardware.
>
> 2. **Fixes a real bug**: Yes - user-visible performance degradation (1-2
>    second hangs) on specific hardware.
>
> 3. **Important issue**: It's a usability issue rather than a
>    crash/security issue. However, hardware quirks for broken behavior
>    are explicitly allowed in stable.
>
> 4. **Small and contained**: The change is minimal - 3 new lines of code
>    plus a new flag definition. It only affects RTS525A devices and
>    doesn't change behavior for any other hardware.
>
> 5. **No new features**: This is a hardware quirk/workaround, which is an
>    explicitly allowed exception to the "no new features" rule.
>
> 6. **Clean application**: The change builds on existing infrastructure
>    (`extra_caps` flags) that exists in all stable trees since v5.11.
>
> **Risk assessment:**
> - **Very low risk**: The quirk only affects RTS525A devices
>   (`PID_525A`). All other devices are completely unaffected.
> - The code pattern is identical to existing quirks
>   (`EXTRA_CAPS_NO_MMC`).
> - The worst case if the quirk is wrong is slightly higher power
>   consumption on RTS525A (no aggressive PM = card reader stays powered).
>
> **Dependencies:**
> None. The change uses existing infrastructure (`extra_caps`,
> `CHK_PCI_PID`, `PID_525A`) that has been present since before v5.11.
>
> ### Verification
>
> - **git log** showed `rtd3_en` / `MMC_CAP_AGGRESSIVE_PM` was introduced
>   in commit `5b4258f6721f4` (v5.11), confirming all current stable trees
>   have the affected code.
> - **git tag --contains** confirmed the runtime PM commit is in stable
>   trees (p-5.15, p-6.1, p-6.12).
> - **Grep for EXTRA_CAPS_** confirmed the existing quirk flag pattern
>   (NO_MMC at bit 7, SD_EXPRESS at bit 8, new flag at bit 9 - clean
>   progression).
> - **lore.kernel.org fetch** confirmed the bug report describes real
>   user-reported 1-2 second hangs on RTS525A with concrete reproduction
>   steps.
> - **Code review** verified the change only adds a condition check and
>   flag - no behavioral change for non-RTS525A devices.
> - The commit was signed off by Greg Kroah-Hartman, the stable tree
>   maintainer, indicating it went through proper review.
> - Could NOT verify whether any stable tree has already picked this up
>   (unverified, but not relevant to the YES/NO decision).
>
> ### Conclusion
>
> This is a textbook hardware quirk for a specific device with a real,
> user-reported issue. It follows existing patterns in the codebase, is
> minimal in scope, and has zero risk to other devices. Hardware quirks
> are explicitly listed as appropriate for stable backporting. The
> affected code exists in all current stable trees (5.15+).
>
> **YES**
>
>  drivers/misc/cardreader/rts5249.c | 3 +++
>  drivers/mmc/host/rtsx_pci_sdmmc.c | 4 ++--
>  include/linux/rtsx_pci.h          | 1 +
>  3 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/cardreader/rts5249.c b/drivers/misc/cardreader/rts5249.c
> index 38aefd8db452a..87d576a03e68e 100644
> --- a/drivers/misc/cardreader/rts5249.c
> +++ b/drivers/misc/cardreader/rts5249.c
> @@ -78,6 +78,9 @@ static void rtsx_base_fetch_vendor_settings(struct rtsx_pcr *pcr)
>         if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A))
>                 pcr->rtd3_en = rtsx_reg_to_rtd3_uhsii(reg);
>
> +       if (CHK_PCI_PID(pcr, PID_525A))
> +               pcr->extra_caps |= EXTRA_CAPS_NO_AGGRESSIVE_PM;
> +
>         if (rtsx_check_mmc_support(reg))
>                 pcr->extra_caps |= EXTRA_CAPS_NO_MMC;
>         pcr->sd30_drive_sel_3v3 = rtsx_reg_to_sd30_drive_sel_3v3(reg);
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index 4db3328f46dfb..8df60000b5b41 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -1497,8 +1497,8 @@ static void realtek_init_host(struct realtek_pci_sdmmc *host)
>         mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SD_HIGHSPEED |
>                 MMC_CAP_MMC_HIGHSPEED | MMC_CAP_BUS_WIDTH_TEST |
>                 MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
> -       if (pcr->rtd3_en)
> -               mmc->caps = mmc->caps | MMC_CAP_AGGRESSIVE_PM;
> +       if (pcr->rtd3_en && !(pcr->extra_caps & EXTRA_CAPS_NO_AGGRESSIVE_PM))
> +               mmc->caps |= MMC_CAP_AGGRESSIVE_PM;
>         mmc->caps2 = MMC_CAP2_NO_PRESCAN_POWERUP | MMC_CAP2_FULL_PWR_CYCLE |
>                 MMC_CAP2_NO_SDIO;
>         mmc->max_current_330 = 400;
> diff --git a/include/linux/rtsx_pci.h b/include/linux/rtsx_pci.h
> index 3c5689356004e..f6122349c00ec 100644
> --- a/include/linux/rtsx_pci.h
> +++ b/include/linux/rtsx_pci.h
> @@ -1230,6 +1230,7 @@ struct rtsx_pcr {
>  #define EXTRA_CAPS_MMC_8BIT            (1 << 5)
>  #define EXTRA_CAPS_NO_MMC              (1 << 7)
>  #define EXTRA_CAPS_SD_EXPRESS          (1 << 8)
> +#define EXTRA_CAPS_NO_AGGRESSIVE_PM    (1 << 9)
>         u32                             extra_caps;
>
>  #define IC_VER_A                       0
> --
> 2.51.0
>

Re: [PATCH AUTOSEL 6.19-5.15] mmc: rtsx_pci: add quirk to disable MMC_CAP_AGGRESSIVE_PM for RTS525A

[Sasha Levin]

On Thu, Feb 19, 2026 at 11:29:38AM +0100, Ulf Hansson wrote:
>On Thu, 19 Feb 2026 at 03:04, Sasha Levin <sashal@kernel.org> wrote:
>>
>> From: Matthew Schwartz <matthew.schwartz@linux.dev>
>>
>> [ Upstream commit 5f0bf80cc5e04d31eeb201683e0b477c24bd18e7 ]
>>
>> Using MMC_CAP_AGGRESSIVE_PM on RTS525A card readers causes game
>> performance issues when the card reader comes back from idle into active
>> use. This can be observed in Hades II when loading new sections of the
>> game or menu after the card reader puts itself into idle, and presents
>> as a 1-2 second hang.
>>
>> Add EXTRA_CAPS_NO_AGGRESSIVE_PM quirk to allow cardreader drivers to
>> opt-out of aggressive PM, and set it for RTS525A.
>>
>> Closes: https://lore.kernel.org/linux-mmc/ff9a7c20-f465-4afa-bf29-708d4a52974a@linux.dev/
>> Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
>> Link: https://patch.msgid.link/20260103204226.71752-1-matthew.schwartz@linux.dev
>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>
>NAK.
>
>This patch is reverted in mainline, as it's not the proper fix.

Dropped, thanks.

-- 
Thanks,
Sasha

Re: [PATCH AUTOSEL 6.19-6.1] mmc: rtsx: reset power state on suspend

[Sasha Levin]

On Thu, Feb 19, 2026 at 11:27:35AM +0100, Ulf Hansson wrote:
>On Thu, 19 Feb 2026 at 03:04, Sasha Levin <sashal@kernel.org> wrote:
>>
>> From: Matthew Schwartz <matthew.schwartz@linux.dev>
>>
>> [ Upstream commit eac85fbd0867c25ac517f58fae401d65c627edff ]
>>
>> When rtsx_pci suspends, the card reader hardware powers off but the sdmmc
>> driver's prev_power_state remains as MMC_POWER_ON. This causes sd_power_on
>> to skip reinitialization on the next I/O request, leading to DMA transfer
>> timeouts and errors on resume 20% of the time.
>>
>> Add a power_off slot callback so the PCR can notify the sdmmc driver
>> during suspend. The sdmmc driver resets prev_power_state, and sd_request
>> checks this to reinitialize the card before the next I/O.
>>
>> Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
>> Link: https://patch.msgid.link/20260105060236.400366-2-matthew.schwartz@linux.dev
>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>
>NAK.
>
>This patch is reverted in mainline, as it's not the proper fix.

Dropped, thanks.

-- 
Thanks,
Sasha