Hi Marek, 2018-09-21 12:51 GMT+02:00, Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx>: > Hi Marek, > > 2018-09-21 10:18 GMT+02:00, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>: >> Hi Janusz, >> >> On 2018-09-20 18:21, Janusz Krzysztofik wrote: >>> On Thursday, September 20, 2018 5:48:22 PM CEST Janusz Krzysztofik >>> wrote: >>>> On Thursday, September 20, 2018 12:11:48 PM CEST Marek Szyprowski >>>> wrote: >>>>> On 2018-09-02 14:01, Janusz Krzysztofik wrote: >>>>>> Certain GPIO descriptor arrays returned by gpio_get_array() may >>>>>> contain >>>>>> information on direct mapping of array members to pins of a single >>>>>> GPIO >>>>>> chip in hardware order. In such cases, bitmaps of values can be >>>>>> passed >>>>>> directly from/to the chip's .get/set_multiple() callbacks without >>>>>> wasting time on iterations. >>>>>> >>>>>> Add respective code to gpiod_get/set_array_bitmap_complex() >>>>>> functions. >>>>>> Pins not applicable for fast path are processed as before, skipping >>>>>> over the 'fast' ones. >>>>>> >>>>>> Cc: Jonathan Corbet <corbet@xxxxxxx> >>>>>> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> >>>>> I've just noticed that this patch landed in today's linux-next. Sadly >>>>> it >>>>> breaks booting of Exynos5250-based Samsung Snow Chromebook (ARM 32bit, >>>>> device-tree source arch/arm/boot/dts/exynos5250-snow.dts). >>>>> >>>>> Booting hangs after detecting MMC cards. Reverting this patch fixes >>>>> the >>>>> boot. I will try later to add some debugs and investigate it further >>>>> what >>>>> really happens when booting hangs. >>>> Hi Marek, >>>> >>>> Thanks for reporting. Could you please try the following fix? >>> Hi again, >>> >>> I realized the patch was not correct, j, not i, should be updated in >>> second >>> hunk. Please try the following one. >>> >>> Thanks, >>> Janusz >>> >>> >From a919c504850f6cb40e8e81267a3a37537f7c4fd4 Mon Sep 17 00:00:00 2001 >>> From: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> >>> Date: Thu, 20 Sep 2018 17:37:21 +0200 >>> Subject: [PATCH] gpiolib: Fix bitmap index not updated >>> While skipping fast path bits, bitmap index is not updated with next >>> found zero bit position. Fix it. >>> >>> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> >> >> This one also doesn't help. A quick compare of logs with this version and >> a working system shows, that with your patch (and fix) there are no calls >> to >> gpx0-2 pin (which are a part of mmc pwrseq), what causes mmc failure. If >> you need any more information (what kind of logs will help?), let me >> know. One more question. You said before that booting hanged after detecting MMC cards. Without the fix, I could imagine it keeps iterating with index not updated and simply never returns from gpiod_get/set_array_bitmap_complex(). Is the behaviour you observe the same with the fix applied? Thanks, Janusz > There is a debug message on array_info content available at the end of > gpiod_get_array(), could you please activate it and post the message so > we can understand better what is going on? > > On the other hand, I've had a look your device-tree configuration and > it looks like that specific setup won't benefit from the fast bitmap path. > You have pin 2 at position 0 and pin 1 at position 1 of the array. > Hence, the fast bitmap path covers only pin 1, and pin 2 is processed > by the old path with apparently buggy code for skipping over fast pins. > > As a temporary workaround, you could try to revert the order of pins in > your dts file (pin 1 at position 0, pin 2 at 1) and the mmc pwrseq code > should work for you again by taking the original old path, not skipping > over fast pins. Results of such check may also help us to better > understand and resolve the issue. > > Thanks, > Janusz > >> >>> --- >>> drivers/gpio/gpiolib.c | 7 ++++--- >>> 1 file changed, 4 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c >>> index a53d17745d21..369bdd358fcc 100644 >>> --- a/drivers/gpio/gpiolib.c >>> +++ b/drivers/gpio/gpiolib.c >>> @@ -2880,7 +2880,7 @@ int gpiod_get_array_value_complex(bool raw, bool >>> can_sleep, >>> __set_bit(hwgpio, mask); >>> >>> if (array_info) >>> - find_next_zero_bit(array_info->get_mask, >>> + i = find_next_zero_bit(array_info->get_mask, >>> array_size, i); >>> else >>> i++; >>> @@ -2905,7 +2905,8 @@ int gpiod_get_array_value_complex(bool raw, bool >>> can_sleep, >>> trace_gpio_value(desc_to_gpio(desc), 1, value); >>> >>> if (array_info) >>> - find_next_zero_bit(array_info->get_mask, i, j); >>> + j = find_next_zero_bit(array_info->get_mask, i, >>> + j); >>> else >>> j++; >>> } >>> @@ -3192,7 +3193,7 @@ int gpiod_set_array_value_complex(bool raw, bool >>> can_sleep, >>> } >>> >>> if (array_info) >>> - find_next_zero_bit(array_info->set_mask, >>> + i = find_next_zero_bit(array_info->set_mask, >>> array_size, i); >>> else >>> i++; >> >> Best regards >> -- >> Marek Szyprowski, PhD >> Samsung R&D Institute Poland >> >> >
