From: Marek Vasut marex@denx.de
stable inclusion from stable-5.10.65 commit 1a0014c1c62cb2d7d8cc0d9d6ffd398c7ba79ccc bugzilla: 182361 https://gitee.com/openeuler/kernel/issues/I4EH3U
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 9891cb54445bc65bf156bda416b6215048c7f617 ]
In case the DRAM is under high load, the MXSFB FIFO might underflow and that causes visible artifacts. This could be triggered on i.MX8MM using e.g. "$ memtester 128M" on a device with 1920x1080 panel. The first "Stuck Address" test of the memtester will completely corrupt the image on the panel and leave the MXSFB FIFO in odd state.
To avoid this underflow, increase number of outstanding requests to DRAM from 2 to 16, which is the maximum. This mitigates the issue and it can no longer be triggered.
Fixes: 45d59d704080 ("drm: Add new driver for MXSFB controller") Signed-off-by: Marek Vasut marex@denx.de Cc: Daniel Abrecht public@danielabrecht.ch Cc: Emil Velikov emil.l.velikov@gmail.com Cc: Laurent Pinchart laurent.pinchart@ideasonboard.com Cc: Lucas Stach l.stach@pengutronix.de Cc: Stefan Agner stefan@agner.ch Reviewed-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Sam Ravnborg sam@ravnborg.org Link: https://patchwork.freedesktop.org/patch/msgid/20210620224759.189351-1-marex@... Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/gpu/drm/mxsfb/mxsfb_drv.c | 3 +++ drivers/gpu/drm/mxsfb/mxsfb_drv.h | 1 + drivers/gpu/drm/mxsfb/mxsfb_kms.c | 8 ++++++++ drivers/gpu/drm/mxsfb/mxsfb_regs.h | 8 ++++++++ 4 files changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index 17f26052e845..f31e8ef3c258 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -51,6 +51,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = { .hs_wdth_mask = 0xff, .hs_wdth_shift = 24, .has_overlay = false, + .has_ctrl2 = false, }, [MXSFB_V4] = { .transfer_count = LCDC_V4_TRANSFER_COUNT, @@ -59,6 +60,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = { .hs_wdth_mask = 0x3fff, .hs_wdth_shift = 18, .has_overlay = false, + .has_ctrl2 = true, }, [MXSFB_V6] = { .transfer_count = LCDC_V4_TRANSFER_COUNT, @@ -67,6 +69,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = { .hs_wdth_mask = 0x3fff, .hs_wdth_shift = 18, .has_overlay = true, + .has_ctrl2 = true, }, };
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h b/drivers/gpu/drm/mxsfb/mxsfb_drv.h index 399d23e91ed1..7c720e226fdf 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h @@ -22,6 +22,7 @@ struct mxsfb_devdata { unsigned int hs_wdth_mask; unsigned int hs_wdth_shift; bool has_overlay; + bool has_ctrl2; };
struct mxsfb_drm_private { diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index bc6d19d999ac..007ea29abfcc 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c @@ -107,6 +107,14 @@ static void mxsfb_enable_controller(struct mxsfb_drm_private *mxsfb) clk_prepare_enable(mxsfb->clk_disp_axi); clk_prepare_enable(mxsfb->clk);
+ /* Increase number of outstanding requests on all supported IPs */ + if (mxsfb->devdata->has_ctrl2) { + reg = readl(mxsfb->base + LCDC_V4_CTRL2); + reg &= ~CTRL2_SET_OUTSTANDING_REQS_MASK; + reg |= CTRL2_SET_OUTSTANDING_REQS_16; + writel(reg, mxsfb->base + LCDC_V4_CTRL2); + } + /* If it was disabled, re-enable the mode again */ writel(CTRL_DOTCLK_MODE, mxsfb->base + LCDC_CTRL + REG_SET);
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_regs.h b/drivers/gpu/drm/mxsfb/mxsfb_regs.h index df90e960f495..694fea13e893 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_regs.h +++ b/drivers/gpu/drm/mxsfb/mxsfb_regs.h @@ -15,6 +15,7 @@ #define LCDC_CTRL 0x00 #define LCDC_CTRL1 0x10 #define LCDC_V3_TRANSFER_COUNT 0x20 +#define LCDC_V4_CTRL2 0x20 #define LCDC_V4_TRANSFER_COUNT 0x30 #define LCDC_V4_CUR_BUF 0x40 #define LCDC_V4_NEXT_BUF 0x50 @@ -61,6 +62,13 @@ #define CTRL1_CUR_FRAME_DONE_IRQ_EN BIT(13) #define CTRL1_CUR_FRAME_DONE_IRQ BIT(9)
+#define CTRL2_SET_OUTSTANDING_REQS_1 0 +#define CTRL2_SET_OUTSTANDING_REQS_2 (0x1 << 21) +#define CTRL2_SET_OUTSTANDING_REQS_4 (0x2 << 21) +#define CTRL2_SET_OUTSTANDING_REQS_8 (0x3 << 21) +#define CTRL2_SET_OUTSTANDING_REQS_16 (0x4 << 21) +#define CTRL2_SET_OUTSTANDING_REQS_MASK (0x7 << 21) + #define TRANSFER_COUNT_SET_VCOUNT(x) (((x) & 0xffff) << 16) #define TRANSFER_COUNT_GET_VCOUNT(x) (((x) >> 16) & 0xffff) #define TRANSFER_COUNT_SET_HCOUNT(x) ((x) & 0xffff)