Re: [PATCH 0/4] mmc: meson-gx: chained descriptor fixup and improvements

[Martin Blumenstingl <martin.blumenstingl@googlemail.com>]

Hi Jerome,

On Thu, Dec 6, 2018 at 4:18 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
>
> The goal of the patchset was mainly to address the following warning:
>
> WARNING: CPU: 0 PID: 0 at /usr/src/kernel/drivers/mmc/host/meson-gx-mmc.c:1025 meson_mmc_irq+0xc0/0x1e0
> Modules linked in: crc32_ce crct10dif_ce ipv6 overlay
> CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         4.19.1 #1
> Hardware name: Some A113 Board (DT)
> pstate: 40000085 (nZcv daIf -PAN -UAO)
> pc : meson_mmc_irq+0xc0/0x1e0
> lr : __handle_irq_event_percpu+0x70/0x180
> sp : ffff000008003980
> x29: ffff000008003980 x28: 0000000000000000
> [...]
> x1 : ffff80001a71bd40 x0 : 0000000000000000
> Call trace:
>  meson_mmc_irq+0xc0/0x1e0
>  __handle_irq_event_percpu+0x70/0x180
>  handle_irq_event_percpu+0x34/0x88
>  handle_irq_event+0x48/0x78
>  handle_fasteoi_irq+0xa0/0x180
>  generic_handle_irq+0x24/0x38
>  __handle_domain_irq+0x5c/0xb8
>  gic_handle_irq+0x58/0xa8
>
> This happens when using the chained descriptor mode. If there is an
> error, we call mmc_request_done(), loosing any reference to the cmd. It
> turns out that the chained descriptor does really stops when we do so, at
> least not completly. Most of the time, it can be seen with this harmless
> warning because the descriptor will raise another unexpected IRQ. On rare
> occasion, it will completly break the MMC.
>
> This is mostly adressed by patch #1.
> With this fixed, I took (yet) another look at the ultra-high speed modes
> and the tuning.
>
> I came up with new settings in patch 3 and 4. I've tested them on eMMC,
> sdcard and sdio on the following platforms:
>  * gxbb p200
>  * gxl p230, libretech (eMMC only), kvim.
>  * axg s400
>
> So far, these new settings seems to be working great but I think it
> would be nice if others could test this and provide their feedback.
> This why  patch 3 and 4 are RFT tagged.
>
> Jerome Brunet (4):
>   mmc: meson-gx: make sure the descriptor is stopped on errors
>   mmc: meson-gx: remove useless lock
>   mmc: meson-gx: align default phase on soc vendor tree
>   mmc: meson-gx: add signal resampling
I gave all four patches a go on my Khadas VIM2 Basic (16GB eMMC).
regardless of whether I have your patch applied or not: eMMC
sporadically fails tuning (if I reboot the board a few times it starts
to work)
[    4.172686] mmc1: tuning execution failed: -5
[    4.182535] mmc1: error -5 whilst initialising MMC card

I'm not sure if this issue is specific to my Khadas VIM2 so this is
*not* a nack for your patches.


Regards
Martin