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[ Upstream commit9d957a959b] During suspend/resume, mtk_eint_mask may be called while wake_mask is active. For example, this happens if a wake-source with an active interrupt handler wakes the system: irq/pm.c:irq_pm_check_wakeup would disable the interrupt, so that it can be handled later on in the resume flow. However, this may happen before mtk_eint_do_resume is called: in this case, wake_mask is loaded, and cur_mask is restored from an older copy, re-enabling the interrupt, and causing an interrupt storm (especially for level interrupts). Step by step, for a line that has both wake and interrupt enabled: 1. cur_mask[irq] = 1; wake_mask[irq] = 1; EINT_EN[irq] = 1 (interrupt enabled at hardware level) 2. System suspends, resumes due to that line (at this stage EINT_EN == wake_mask) 3. irq_pm_check_wakeup is called, and disables the interrupt => EINT_EN[irq] = 0, but we still have cur_mask[irq] = 1 4. mtk_eint_do_resume is called, and restores EINT_EN = cur_mask, so it reenables EINT_EN[irq] = 1 => interrupt storm as the driver is not yet ready to handle the interrupt. This patch fixes the issue in step 3, by recording all mask/unmask changes in cur_mask. This also avoids the need to read the current mask in eint_do_suspend, and we can remove mtk_eint_chip_read_mask function. The interrupt will be re-enabled properly later on, sometimes after mtk_eint_do_resume, when the driver is ready to handle it. Fixes:58a5e1b64b("pinctrl: mediatek: Implement wake handler and suspend resume") Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Acked-by: Sean Wang <sean.wang@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.