Re: [PATCH] dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout

[Geert Uytterhoeven]

Hi Alex,

On Wed, 1 Apr 2026 at 10:27, Alex Bereza <alex@bereza.email> wrote:
> On Wed Apr 1, 2026 at 7:23 AM CEST, Suraj Gupta wrote:
> >> Rename XILINX_DMA_LOOP_COUNT to XILINX_DMA_POLL_TIMEOUT_US because the
> >> former is incorrect. It is a timeout value for polling various register
> >> bits in microseconds. It is not a loop count. Add a constant
> >> XILINX_DMA_POLL_DELAY_US for delay_us value.
> >
> > Please split this change in a new patch.
>
> Ok, will send a v2.
>
> >> Fixes: 7349a69cf312 ("iopoll: Do not use timekeeping in read_poll_timeout_atomic()")
> >
> > This patch doesn't fixes anything in iopoll, please use correct fixes tag.

Fixes-tag are also used as guidelines, to indicate which patches
are also needed when backporting something.  I.e. if 7349a69cf312 is
ever backported, any other commits that contain "Fixes: 7349a69cf312"
should be backported, too.  So having this Fixes-tag, in addition to
another xilinx_dma-specific one, sounds fine to me.

> Ok, but I'm not sure what would be the correct fixes tag then? I though I need to reference
> 7349a69cf312 in fixes tag because this is the actual change that surfaced the CPU stall issue that I
> want to fix in this driver. I'm fixing the call sites of xilinx_dma_poll_timeout but they were added
> in different commits. Should I add all of them? That would be the following then:
>
> Fixes: 9495f2648287 ("dmaengine: xilinx_vdma: Use readl_poll_timeout instead of do while loop's")
> Fixes: 676f9c26c330 ("dmaengine: xilinx: fix device_terminate_all() callback for AXI CDMA")

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds