From cb18f536e0f013e3cb1fd9cd90c33f9e24d3892e Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 20 Feb 2020 13:30:12 +0100 Subject: [PATCH] drm/exynos: dsi: fix workaround for the legacy clock name [ Upstream commit c0fd99d659ba5582e09625c7a985d63fc2ca74b5 ] Writing to the built-in strings arrays doesn't work if driver is loaded as kernel module. This is also considered as a bad pattern. Fix this by adding a call to clk_get() with legacy clock name. This fixes following kernel oops if driver is loaded as module: Unable to handle kernel paging request at virtual address bf047978 pgd = (ptrval) [bf047978] *pgd=59344811, *pte=5903c6df, *ppte=5903c65f Internal error: Oops: 80f [#1] SMP ARM Modules linked in: mc exynosdrm(+) analogix_dp rtc_s3c exynos_ppmu i2c_gpio CPU: 1 PID: 212 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200219 #326 videodev: Linux video capture interface: v2.00 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at exynos_dsi_probe+0x1f0/0x384 [exynosdrm] LR is at exynos_dsi_probe+0x1dc/0x384 [exynosdrm] ... Process systemd-udevd (pid: 212, stack limit = 0x(ptrval)) ... [] (exynos_dsi_probe [exynosdrm]) from [] (platform_drv_probe+0x6c/0xa4) [] (platform_drv_probe) from [] (really_probe+0x210/0x350) [] (really_probe) from [] (driver_probe_device+0x60/0x1a0) [] (driver_probe_device) from [] (device_driver_attach+0x58/0x60) [] (device_driver_attach) from [] (__driver_attach+0x80/0xbc) [] (__driver_attach) from [] (bus_for_each_dev+0x68/0xb4) [] (bus_for_each_dev) from [] (bus_add_driver+0x130/0x1e8) [] (bus_add_driver) from [] (driver_register+0x78/0x110) [] (driver_register) from [] (exynos_drm_init+0xe8/0x11c [exynosdrm]) [] (exynos_drm_init [exynosdrm]) from [] (do_one_initcall+0x50/0x220) [] (do_one_initcall) from [] (do_init_module+0x60/0x210) [] (do_init_module) from [] (load_module+0x1c0c/0x2310) [] (load_module) from [] (sys_finit_module+0xac/0xbc) [] (sys_finit_module) from [] (ret_fast_syscall+0x0/0x54) Exception stack(0xd979bfa8 to 0xd979bff0) ... ---[ end trace db16efe05faab470 ]--- Signed-off-by: Marek Szyprowski Reviewed-by: Andrzej Hajda Signed-off-by: Inki Dae Signed-off-by: Sasha Levin --- drivers/gpu/drm/exynos/exynos_drm_dsi.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index aef18f807e38..366c975cde5b 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -1754,9 +1754,10 @@ static int exynos_dsi_probe(struct platform_device *pdev) dsi->clks[i] = devm_clk_get(dev, clk_names[i]); if (IS_ERR(dsi->clks[i])) { if (strcmp(clk_names[i], "sclk_mipi") == 0) { - strcpy(clk_names[i], OLD_SCLK_MIPI_CLK_NAME); - i--; - continue; + dsi->clks[i] = devm_clk_get(dev, + OLD_SCLK_MIPI_CLK_NAME); + if (!IS_ERR(dsi->clks[i])) + continue; } dev_info(dev, "failed to get the clock: %s\n", -- 2.20.1