On 03/31/2016 02:16 AM, Enric Balletbo Serra wrote: > 2016-03-24 17:22 GMT+01:00 Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>: >> On Thu, Mar 24, 2016 at 09:06:45AM -0700, Doug Anderson wrote: >>> Russell, >> ... >>> Presumably this is similar to what you saw: the host saw the CRC error >>> but the card knew nothing about it. Sending the stop command during >>> this time confused the card. Presumably the card was in transfer >>> state during this time? >> >> If the card was in transfer state for a command which expects a stop >> command, and that stop command was issued after the card entered >> the transfer state, then I'd expect the card to handle it... though >> there's always the firmware bug issue. >> >> If the card hadn't entered transfer state at the time the stop command >> was issued.. I think that's more likely to hit card firmware issues. >> >> With the tuning commands, there's another case you can hit though: >> the data transfer may have completed before you get around to sending >> the stop command. >> >> That's why, for sdhci, I came to the conclusion that waiting for the >> data transfer to complete or timeout was the best solution for SDHCI. >> > > In fact I only saw the problem with dw_mmc-exynos, on dw_mmc-rockchip > it doesn't happen because it enables the DW_MCI_QUIRK_BROKEN_DTO > behaviour. What does this is use a kernel timer to signal when DTO > interrupt does NOT come. Note that if I disable this quirk I can also > saw the problem on rockchip. Did you see the problem with exynos? Could you share which exynos chip you use? Then i can check this with all exynos. > >> Maybe, if sending a STOP command does cause card firmware issues, then: >> >> 1) it provides evidence that trying to send a stop command on response >> CRC error is the wrong thing to do (it was talked about making SDHCI >> do this.) >> > > Seems the same here, so guess is the wrong thing to do. > >> 2) it suggests that the solution I came up with for SDHCI is the better >> solution, rather than trying to immediately recover the situation by >> sending a STOP command. >> > > I'm wondering if just enable this quirk on exynos too is the proper > solution. Unfortunately I don't have enough documentation to check > differences between those controllers. > Also will really help have access to some hardware that uses > dw_mmc-pltfm to check if, like on exynos, same issue is triggered. > Anyone with the hardware who can do some tests? I want to remove all quirks for dwmmc controller. (in progressing with Shawn.) > > >> Maybe dw-mmc can do something similar, but with the lack of data transfer >> timeout, maybe it's possible to do something with a kernel timer instead, >> and check what the hardware is doing after a response CRC error? >> >> -- >> RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ >> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up >> according to speedtest.net. > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
