This patch series aims at adding support for Exynos7870's DECON in the Exynos7 DECON driver. It introduces a driver data struct so that support for DECON on other SoCs can be added to it in the future.
It also fixes a few bugs in the driver, such as functions receiving bad pointers.
Tested on Samsung Galaxy J7 Prime (samsung-on7xelte), Samsung Galaxy A2 Core (samsung-a2corelte), and Samsung Galaxy J6 (samsung-j6lte).
Signed-off-by: Kaustabh Chakraborty kauschluss@disroot.org --- Changes in v2: - Add a new commit to prevent an occasional panic under circumstances. - Rewrite and redo [v1 2/6] to be a more sensible commit. - Link to v1: https://lore.kernel.org/r/20240919-exynosdrm-decon-v1-0-6c5861c1cb04@disroot...
--- Kaustabh Chakraborty (2): drm/exynos: exynos7_drm_decon: fix call of decon_commit() drm/exynos: exynos7_drm_decon: add vblank check in IRQ handling
drivers/gpu/drm/exynos/exynos7_drm_decon.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- base-commit: 0bb71d301869446810a0b13d3da290bd455d7c78 change-id: 20240917-exynosdrm-decon-4c228dd1d2bf
Best regards,
decon_commit() has a condition guard at the beginning:
if (ctx->suspended) return;
But, when it is being called from decon_atomic_enable(), ctx->suspended is still set to true, which prevents its execution. decon_commit() is vital for setting up display timing values, without which the display pipeline fails to function properly. Call the function after ctx->suspended is set to false as a fix.
Cc: stable@vger.kernel.org Fixes: 96976c3d9aff ("drm/exynos: Add DECON driver") Signed-off-by: Kaustabh Chakraborty kauschluss@disroot.org --- drivers/gpu/drm/exynos/exynos7_drm_decon.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c index f91daefa9d2bc5e314c279822047e60ee0d7ca99..43bcbe2e2917df43d7c2d27a9771e892628dd682 100644 --- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c +++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c @@ -583,9 +583,9 @@ static void decon_atomic_enable(struct exynos_drm_crtc *crtc) if (test_and_clear_bit(0, &ctx->irq_flags)) decon_enable_vblank(ctx->crtc);
- decon_commit(ctx->crtc); - ctx->suspended = false; + + decon_commit(ctx->crtc); }
static void decon_atomic_disable(struct exynos_drm_crtc *crtc)
If there's support for another console device (such as a TTY serial), the kernel occasionally panics during boot. The panic message and a relevant snippet of the call stack is as follows:
Unable to handle kernel NULL pointer dereference at virtual address 000000000000000 Call trace: drm_crtc_handle_vblank+0x10/0x30 (P) decon_irq_handler+0x88/0xb4 [...]
Otherwise, the panics don't happen. This indicates that it's some sort of race condition.
Add a check to validate if the drm device can handle vblanks before calling drm_crtc_handle_vblank() to avoid this.
Cc: stable@vger.kernel.org Fixes: 96976c3d9aff ("drm/exynos: Add DECON driver") Signed-off-by: Kaustabh Chakraborty kauschluss@disroot.org --- drivers/gpu/drm/exynos/exynos7_drm_decon.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c index 43bcbe2e2917df43d7c2d27a9771e892628dd682..c0c0f23169c993ac315fc8d7bcbd09ea6ec9966a 100644 --- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c +++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c @@ -636,6 +636,10 @@ static irqreturn_t decon_irq_handler(int irq, void *dev_id) if (!ctx->drm_dev) goto out;
+ /* check if crtc and vblank have been initialized properly */ + if (!drm_dev_has_vblank(ctx->drm_dev)) + goto out; + if (!ctx->i80_if) { drm_crtc_handle_vblank(&ctx->crtc->base);
linux-stable-mirror@lists.linaro.org
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Kaustabh Chakraborty