Re: [PATCH v2] pci: quirks: Disable native PCIe hotplug on MSI Claw A8 root bridge

["Derek J. Clark" <derekjohn.clark@gmail.com>]

On August 11, 2026 5:59:09 PM GMT+09:00, Lukas Wunner <lukas@wunner.de> wrote:
>[cc += Ulf, start of thread is here:
>https://lore.kernel.org/all/20260806214808.1202819-1-derekjohn.clark@gmail.com/
>]
>
>On Tue, Aug 11, 2026 at 07:19:12AM +0200, Lukas Wunner wrote:
>> On Mon, Aug 10, 2026 at 01:57:58PM -0700, Derek John Clark wrote:
>> > I was able to drill down further. When the mmc device gets to
>> > blk_report_disk_dead() in block/genhd.c there is an xa_for_each loop.
>> > On the second loop of that it seems to hang in bdev_mark_dead(). That
>> > sets a callback that runs fs_bdev_mark_dead() which then runs
>> > sync_filesystem(). This is all hit because the "surprise" bool is set
>> > to false unconditionally in __del_gendisk().
>> > 
>> > Commenting out this from __del_gendisk():
>> > if (!test_bit(GD_DEAD, &disk->state))
>> >  blk_report_disk_dead(disk, false);
>> > 
>> > Avoids the hang.
>> 
>> Thank you so much, you've root-caused the issue:  We're missing a call
>> to blk_mark_disk_dead() at the top of rtsx_pci_sdmmc_drv_remove()
>> if the underlying pci_dev is marked disconnected.  Let me get back
>> to you with a fix in a bit.
>
>So the completely untested patch below might be an upstreamable approach.
>I'm adding MMC maintainer Ulf to cc in case he has early feedback.
>

Great, I'll give it a test soon and follow up. 

>If this works, feel free to submit a proper patch and claim authorship
>if you want.  I'll gladly let you have that given the amount of time
>you've already sunk into it.  If you'd rather have me submit a patch
>(and deal with any regressions caused by it), I'll be happy to do
>that as well.  Thanks!
>

I think tested by tags will be sufficient once I've completed that. The shape of your patch is a bit different than what I was working on and is a better approach. I appreciate your help on this so far.

Thanks,
Derek 

>-- >8 --
>
>diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
>index 0274e8d..1a82233 100644
>--- a/drivers/mmc/core/block.c
>+++ b/drivers/mmc/core/block.c
>@@ -2978,8 +2978,11 @@ static int mmc_blk_alloc_parts(struct mmc_card *card, struct mmc_blk_data *md)
> 	return 0;
> }
> 
>-static void mmc_blk_remove_req(struct mmc_blk_data *md)
>+static void mmc_blk_remove_req(struct mmc_card *card, struct mmc_blk_data *md)
> {
>+	if (mmc_card_removed(card))
>+		blk_mark_disk_dead(md->disk);
>+
> 	/*
> 	 * Flush remaining requests and free queues. It is freeing the queue
> 	 * that stops new requests from being accepted.
>@@ -3006,7 +3009,7 @@ static void mmc_blk_remove_parts(struct mmc_card *card,
> 	list_for_each_safe(pos, q, &md->part) {
> 		part_md = list_entry(pos, struct mmc_blk_data, part);
> 		list_del(pos);
>-		mmc_blk_remove_req(part_md);
>+		mmc_blk_remove_req(card, part_md);
> 	}
> }
> 
>@@ -3252,7 +3255,7 @@ static int mmc_blk_probe(struct mmc_card *card)
> 
> out:
> 	mmc_blk_remove_parts(card, md);
>-	mmc_blk_remove_req(md);
>+	mmc_blk_remove_req(card, md);
> out_free:
> 	destroy_workqueue(card->complete_wq);
> 	return ret;
>@@ -3273,7 +3276,7 @@ static void mmc_blk_remove(struct mmc_card *card)
> 	if (!mmc_card_sd_combo(card))
> 		pm_runtime_disable(&card->dev);
> 	pm_runtime_put_noidle(&card->dev);
>-	mmc_blk_remove_req(md);
>+	mmc_blk_remove_req(card, md);
> 	destroy_workqueue(card->complete_wq);
> }
> 
>diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
>index b7ce313..658b241 100644
>--- a/drivers/mmc/core/host.c
>+++ b/drivers/mmc/core/host.c
>@@ -703,3 +703,17 @@ void mmc_free_host(struct mmc_host *host)
> }
> 
> EXPORT_SYMBOL(mmc_free_host);
>+
>+/**
>+ *	mmc_host_set_removed - declare host removed
>+ *	@host: mmc host
>+ *
>+ *	Declare the host (and any inserted card) removed and inaccessible.
>+ */
>+void mmc_host_set_removed(struct mmc_host *host)
>+{
>+	if (host->card)
>+		mmc_card_set_removed(host->card);
>+}
>+
>+EXPORT_SYMBOL(mmc_host_set_removed);
>diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
>index 8dfbc62..3f97659f 100644
>--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
>+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
>@@ -1511,6 +1511,9 @@ static void rtsx_pci_sdmmc_drv_remove(struct platform_device *pdev)
> 	pcr->slots[RTSX_SD_CARD].card_event = NULL;
> 	mmc = host->mmc;
> 
>+	if (pci_dev_is_disconnected(pcr->pci))
>+		mmc_host_set_removed(mmc);
>+
> 	cancel_work_sync(&host->work);
> 
> 	mutex_lock(&host->host_mutex);
>diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>index ba84f02..a240306 100644
>--- a/include/linux/mmc/host.h
>+++ b/include/linux/mmc/host.h
>@@ -588,6 +588,7 @@ struct mmc_host {
> int mmc_add_host(struct mmc_host *);
> void mmc_remove_host(struct mmc_host *);
> void mmc_free_host(struct mmc_host *);
>+void mmc_host_set_removed(struct mmc_host *host);
> void mmc_of_parse_clk_phase(struct device *dev,
> 			    struct mmc_clk_phase_map *map);
> int mmc_of_parse(struct mmc_host *host);