Re: [PATCH v2] arm64: dts: renesas: r8a77990: ebisu: Enable HS400 of SDHI3

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Simon,

On Fri, Jan 18, 2019 at 1:25 PM Simon Horman <horms+renesas@verge.net.au> wrote:
> Enable HS400 of SDHI3 using the corresponding DT property.
> No further changes are required.
>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Using "hdparm -tT /dev/mmcblk0"

HS200:

 Timing cached reads:   694 MB in  2.00 seconds = 346.60 MB/sec
 Timing buffered disk reads: 434 MB in  3.00 seconds = 144.56 MB/sec

HS400:

 Timing cached reads:   696 MB in  2.00 seconds = 348.20 MB/sec
 Timing buffered disk reads: 446 MB in  3.00 seconds = 148.65 MB/sec

No real difference.

Note that "dd" gives me very fluctuating results (all for HS400):

root@ebisu:~# dd if=/dev/mmcblk0 of=/dev/null bs=1M count=128 iflag=direct
128+0 records in
128+0 records out
134217728 bytes (134 MB, 128 MiB) copied, 3.20103 s, 41.9 MB/s
root@ebisu:~# dd if=/dev/mmcblk0 of=/dev/null bs=1M count=128 iflag=direct
128+0 records in
128+0 records out
134217728 bytes (134 MB, 128 MiB) copied, 1.15324 s, 116 MB/s
128+0 records in
128+0 records out
134217728 bytes (134 MB, 128 MiB) copied, 1.82701 s, 73.5 MB/s

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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