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R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Realtek card reader [10ec:522a] (rev 01) discard/fstrim support

I have bought a new laptop recently and almost everything has worked out of the box and I'm still getting to know the quirks of the new hardware. One of the quirks is related to the card reader:

lspci -vnn -s 02:00.0
02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader [10ec:522a] (rev 01)
	Subsystem: Lenovo Device [17aa:5048]
	Flags: bus master, fast devsel, latency 0, IRQ 124
	Memory at f1100000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: [40] Power Management version 3
	Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
	Capabilities: [70] Express Endpoint, MSI 00
	Capabilities: [100] Advanced Error Reporting
	Capabilities: [140] Device Serial Number 00-00-00-01-00-4c-e0-00
	Capabilities: [150] Latency Tolerance Reporting
	Capabilities: [158] L1 PM Substates
	Kernel driver in use: rtsx_pci
	Kernel modules: rtsx_pci

This being a PCIe card reader I assumed it would support the MMC erase commands, which would allow me to use blkdiscard (on the whole card) or mount filesystems with the discard option and issue fstrim, however when trying to use fstrim I get this message: "fstrim: .: the discard operation is not supported".

What I'm wondering is, if anyone with a similar card reader or any other card reader supported by the rtsx_pci driver has been able to use fstrim/blkdiscard at any point in time. From what I could tell from googling this driver seems to be recent(ish) so that may not be implemented yet, but if it is a regression it would be a matter of submitting a bug report upstream.

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R00KIE
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