Re: [PATCH] mmc: sunxi: remove output of virtual base address

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On 18/07/18 12:19, Andre Przywara wrote:
Hi,

On 17/07/18 12:43, Maxime Ripard wrote:
1;5202;0c
On Tue, Jul 17, 2018 at 11:09:58AM +0100, Andre Przywara wrote:
Recent Linux versions refuse to print actual virtual kernel addresses,
to not give a hint about the location of the kernel in a randomized virtual
address space. This affects the output of the sunxi MMC controller
driver, which now produces the rather uninformative line:

[    1.482660] sunxi-mmc 1c0f000.mmc: base:0x(____ptrval____) irq:8

Since the virtual base address is not really interesting in the first
place, let's just drop this value. We have the physical address as part
of the DT node name, which is way more useful for debugging purposes.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
  drivers/mmc/host/sunxi-mmc.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 8e7f3e35ee3d..811b08d2d0f2 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -1407,7 +1407,7 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
  	if (ret)
  		goto error_free_dma;
- dev_info(&pdev->dev, "base:0x%p irq:%u\n", host->reg_base, host->irq);
+	dev_info(&pdev->dev, "irq:%u\n", host->irq);

Can't we just remove it? It doesn't look like it brings much value anyway.

Yes, the IRQ value is the virtual Linux number, so equally
non-informative. But this line is the only info message left from the
mmc driver, so since we have scary "deferring probe" messages before,
I'd rather leave this "success!" message in, to help debugging:
# dmesg | grep mmc
[    1.314211] sunxi-mmc 1c0f000.mmc: could not find pctldev for node
/soc/pinctrl@1c20800/mmc0-pins, deferring probe
[    1.324705] sunxi-mmc 1c11000.mmc: could not find pctldev for node
/soc/pinctrl@1c20800/mmc2-pins, deferring probe
[    1.737310] sunxi-mmc 1c0f000.mmc: irq:6
[    1.771255] sunxi-mmc 1c11000.mmc: irq:7
[    1.787003] mmc0: new high speed SDHC card at address 1234

That seems like a pretty effective success message right there ;)

FWIW, I find the easiest tool for sanity-checking driver probe status (if it's not already obvious by stuff working correctly, as above) is /proc/interrupts, followed if necessary by digging into /sys/bus/*/drivers/ for the canonical state of things.

If anything I'd argue for the "scary" probe-deferral messages to be downgraded to dev_dbg, since the average user shouldn't need to care.

Robin.

[    1.796029] mmcblk0: mmc0:1234 SA08G 7.21 GiB
[    1.809093]  mmcblk0: p1 p2 p3
....

We could just say something like: "initialized.". It would be even more
useful if we could print the type of MMC: SD card, SDIO, eMMC, but apart
from eMMC vs. MMC0/1 for the A64 we don't have this information (not
even the index number) at this level, I think.

Cheers,
Andre.

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