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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: [PATCH 4.14 23/39] drm/fb-helper: Round up bits_per_pixel if possible
Date: Tue, 14 Jan 2020 11:01:57 +0100
Message-ID: <20200114094344.125349345@linuxfoundation.org> (raw)
In-Reply-To: <20200114094336.210038037@linuxfoundation.org>

From: Geert Uytterhoeven <geert+renesas@glider.be>

commit f30e27779d3031a092c2a177b7fb76adccc45241 upstream.

When userspace requests a video mode parameter value that is not
supported, frame buffer device drivers should round it up to a supported
value, if possible, instead of just rejecting it.  This allows
applications to quickly scan for supported video modes.

Currently this rule is not followed for the number of bits per pixel,
causing e.g. "fbset -depth N" to fail, if N is smaller than the current
number of bits per pixel.

Fix this by returning an error only if bits per pixel is too large, and
setting it to the current value otherwise.

See also Documentation/fb/framebuffer.rst, Section 2 (Programmer's View
of /dev/fb*").

Fixes: 865afb11949e5bf4 ("drm/fb-helper: reject any changes to the fbdev")
Cc: stable@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191230132734.4538-1-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_fb_helper.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1590,7 +1590,7 @@ int drm_fb_helper_check_var(struct fb_va
 	 * Changes struct fb_var_screeninfo are currently not pushed back
 	 * to KMS, hence fail if different settings are requested.
 	 */
-	if (var->bits_per_pixel != fb->format->cpp[0] * 8 ||
+	if (var->bits_per_pixel > fb->format->cpp[0] * 8 ||
 	    var->xres > fb->width || var->yres > fb->height ||
 	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
 		DRM_DEBUG("fb requested width/height/bpp can't fit in current fb "
@@ -1616,6 +1616,11 @@ int drm_fb_helper_check_var(struct fb_va
 	}
 
 	/*
+	 * Likewise, bits_per_pixel should be rounded up to a supported value.
+	 */
+	var->bits_per_pixel = fb->format->cpp[0] * 8;
+
+	/*
 	 * drm fbdev emulation doesn't support changing the pixel format at all,
 	 * so reject all pixel format changing requests.
 	 */



  parent reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 10:01 [PATCH 4.14 00/39] 4.14.165-stable review Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 01/39] chardev: Avoid potential use-after-free in chrdev_open() Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 02/39] usb: chipidea: host: Disable port power only if previously enabled Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 03/39] ALSA: usb-audio: Apply the sample rate quirk for Bose Companion 5 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 04/39] ALSA: hda/realtek - Add new codec supported for ALCS1200A Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 05/39] ALSA: hda/realtek - Set EAPD control to default for ALC222 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 06/39] kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 07/39] tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 08/39] HID: Fix slab-out-of-bounds read in hid_field_extract Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 09/39] HID: uhid: Fix returning EPOLLOUT from uhid_char_poll Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 10/39] can: gs_usb: gs_usb_probe(): use descriptors of current altsetting Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 11/39] can: mscan: mscan_rx_poll(): fix rx path lockup when returning from polling to irq mode Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 12/39] can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 13/39] gpiolib: acpi: Turn dmi_system_id table into a generic quirk table Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 14/39] gpiolib: acpi: Add honor_wakeup module-option + quirk mechanism Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 15/39] staging: vt6656: set usb_set_intfdata on driver fail Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 16/39] USB: serial: option: add ZLP support for 0x1bc7/0x9010 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 17/39] usb: musb: fix idling for suspend after disconnect interrupt Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 18/39] usb: musb: Disable pullup at init Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 19/39] usb: musb: dma: Correct parameter passed to IRQ handler Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 20/39] staging: comedi: adv_pci1710: fix AI channels 16-31 for PCI-1713 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 21/39] HID: hid-input: clear unmapped usages Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 22/39] Input: add safety guards to input_set_keycode() Greg Kroah-Hartman
2020-01-14 10:01 ` Greg Kroah-Hartman [this message]
2020-01-14 10:01 ` [PATCH 4.14 24/39] drm/dp_mst: correct the shifting in DP_REMOTE_I2C_READ Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 25/39] staging: rtl8188eu: Add device code for TP-Link TL-WN727N v5.21 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 26/39] tty: link tty and port before configuring it as console Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 27/39] tty: always relink the port Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 28/39] mwifiex: fix possible heap overflow in mwifiex_process_country_ie() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 29/39] mwifiex: pcie: Fix memory leak in mwifiex_pcie_alloc_cmdrsp_buf Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 30/39] scsi: bfa: release allocated memory in case of error Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 31/39] rtl8xxxu: prevent leaking urb Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 32/39] ath10k: fix memory leak Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 33/39] arm64: cpufeature: Avoid warnings due to unused symbols Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 34/39] HID: hiddev: fix mess in hiddev_open() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 35/39] USB: Fix: Dont skip endpoint descriptors with maxpacket=0 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 36/39] phy: cpcap-usb: Fix error path when no host driver is loaded Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 37/39] phy: cpcap-usb: Fix flakey host idling and enumerating of devices Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 38/39] netfilter: arp_tables: init netns pointer in xt_tgchk_param struct Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 39/39] netfilter: ipset: avoid null deref when IPSET_ATTR_LINENO is present Greg Kroah-Hartman
2020-01-14 15:02 ` [PATCH 4.14 00/39] 4.14.165-stable review Jon Hunter
2020-01-14 18:15 ` Guenter Roeck
2020-01-14 20:27 ` shuah
2020-01-15  2:08 ` Daniel Díaz

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