From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794415415; b=CJA5sxrJ8OpdVviESK0+Rtzsn9ZW8cZRUSSMJQixLoie41YUDLPESiHcz7edEMLAfZlQ Wy3bZeZ5KRtRjkehTetKTEO4TaIN63UUL6kVmct8uHAOJtQgRrB7R22UIB7f4vqRvADIt alhAXD4rhw1INDT2Qm24fr2FO3RuFOe6yTx/4hlfOcEjNLIk9T1C2NffQuWQt/TnRi9U6 cJ8dfEZ/EeOFrXFJuJNKeymjV0qSSJgN+zkIbXdnORW0vkkv1c0gbqX7jMiViznKzZLSY iIkEvg7N2JFN/b3mMj1SvKQSWBid4CBr9m3pMMYuSDtuGEu0jb4YnJPx7tvekv2tP5A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794415415; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=JVAWdku/BV6JArzug/s9+4laVASF/5k0zCIDqMOBijs=; b=Dwmsmmt3DuG8XxQAZITJUPc3YJ2ZSemDlxZVA0PuhpIOGPjRxXIvIi/vhgpNK+BM0c0c bDdV2SqJC8rrqfHOD44pG6R6hyRkwj1QaGoTajAhIoCKSDCRIEVZ6NYJj2LHz7jdCmOug cjljko574erpF31GpmfherBoQTo2rxMT+zNDkDOxgwzMWcw85p0A94BkZAXb6GSgAAOSN kWnk1VssovHa+pXMTVw5gAVA5I/57NP0N3dvxpWataFQsYO9sxQ9Nf2GVWnH4lHw2G80i El22cM9HDHBubvCbUBbjjqI7zEOE+4AsGDP4nqLt7vbCa14nMNxRsh5/1mHvs5TBong== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eHn3tAKd; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21F39606A331 for ; Wed, 11 Nov 2026 16:43:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eHn3tAKd Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C1941F00A05; Wed, 11 Nov 2026 16:43:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794415415; bh=JVAWdku/BV6JArzug/s9+4laVASF/5k0zCIDqMOBijs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=eHn3tAKdfdrRxi3wjL7GELNb06lWmm2rOyGh5JU42+c7ONrAZHm33Ld8LXC0z/j1O 8Wm04rc7A6EA26cnHbS1p6f58fYIG0JXt2vNDHDUbVJH353QAyVWBcxB0xy6kfKR0B OgVPLa/xqAp1dYUaIKArhATjwJ6XtiHc9BtA3LQZttM2N6jcDb2bgi9qY+qaERX4Av nT4RcuogrGw+FFtwn8W+cWZ9wDA7ysvp1Gs3gmo6xylnKLTEkR+QRsOfHNq9xd5Hf0 4dyatWRIf75VARSlX5klB5sLYzo2u2uGDTLxjS1Ho0dj+ZeToNrms9mnnnsGLPZde5 YbK15s0NpsMvw== From: Sasha Levin To: stable@vger.kernel.org Cc: Adrian Ambrozewicz , Kent Gibson , Bartosz Golaszewski , Sasha Levin Subject: [PATCH 5.10.y] gpiolib: cdev: don't set GPIOD_FLAG_IS_OUT Date: Wed, 11 Nov 2026 11:43:33 -0500 Message-ID: <20261111164319.3304408-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107062504-failed-5.10-974d2712cb15@kernel.org> References: <20261107062504-failed-5.10-974d2712cb15@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Adrian Ambrozewicz [ Upstream commit 974d2712cb15014019595799b3ed68fef5fe9695 ] When a line is requested or reconfigured through the v2 uAPI, gpio_v2_line_config_flags_to_desc_flags() copies the requested configuration into the descriptor flags, GPIOD_FLAG_IS_OUT included, before gpiod_direction_input_nonotify() or gpiod_direction_output_nonotify() asks the driver for the direction. If the driver refuses, for instance with -EOPNOTSUPP from .direction_input() for a line that can only be an output, the ioctl fails but the flag keeps the refused direction. gpiod_free_commit() does not touch GPIOD_FLAG_IS_OUT, so this outlives the failed request, and GPIO_V2_GET_LINEINFO_IOCTL reports the line as an input while the hardware still drives it, until a request without direction flags makes gpiod_request_commit() read the direction back from the driver: GPIO_V2_GET_LINE_IOCTL, line 0, input: -EOPNOTSUPP GPIO_V2_GET_LINEINFO_IOCTL, line 0: input GPIO_V2_GET_LINE_IOCTL, line 0, no direction: ok GPIO_V2_GET_LINEINFO_IOCTL, line 0: output GPIO_V2_LINE_SET_CONFIG_IOCTL updates the flags in the same order. There the line stays requested, and since commit 92ac7de3175e ("gpiolib: don't allow setting values on input lines") GPIO_V2_LINE_SET_VALUES_IOCTL on it then fails with -EPERM, though the line is still an output. A line whose driver refuses to make it an output is likewise reported as one. gpiod_direction_input_nonotify() and gpiod_direction_output_nonotify() set or clear GPIOD_FLAG_IS_OUT themselves once the driver has accepted the direction, emulated open drain and open source included, and nothing between the copy and those calls reads the flag. Leave it to them, as the v1 uAPI already does. The other flags that the helper copies stay as they are. Active low, drive and bias are what gpiod_direction_*() applies, drive and bias possibly before the driver refuses the direction; edges and event clock are the character device's own. None of them is read back from the driver, so there is no earlier state that is more accurate to go back to. A failed request releases the line, which clears them, and a failed reconfiguration leaves the line, like the lines before it, with what was applied up to the failure. Reproduced under QEMU with a test GPIO chip whose line 0 refuses input and line 1 refuses output: both refused requests and both refused reconfigurations leave the line info with the refused direction, and setting the value of the reconfigured output fails with -EPERM. With this change the line info shows the direction of the hardware in all four cases and setting the value works. First seen on real hardware with v6.12. Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Adrian Ambrozewicz Reviewed-by: Kent Gibson Link: https://patch.msgid.link/20261016-gpiolib-cdev-direction-v2-1-aambrozewicz@nvidia.com Signed-off-by: Bartosz Golaszewski [ sashal: adapted flag references to use FLAG_IS_OUT with flags and flagsp ] Signed-off-by: Sasha Levin --- drivers/gpio/gpiolib-cdev.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index a4446d7baa390..f2e47c9e1ab75 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -968,11 +968,6 @@ static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, assign_bit(FLAG_ACTIVE_LOW, flagsp, flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); - if (flags & GPIO_V2_LINE_FLAG_OUTPUT) - set_bit(FLAG_IS_OUT, flagsp); - else if (flags & GPIO_V2_LINE_FLAG_INPUT) - clear_bit(FLAG_IS_OUT, flagsp); - assign_bit(FLAG_EDGE_RISING, flagsp, flags & GPIO_V2_LINE_FLAG_EDGE_RISING); assign_bit(FLAG_EDGE_FALLING, flagsp, -- 2.53.0